Category Archives: Botany

RHS Level 3: Plant taxonomy, structure, and function

  1. Understand the Plant Kingdom and the taxonomic hierarchy.

1.1 Describe the major groups of the Plant Kingdom.

List the main groups within bryophytes, pteridophytes, gymnosperms and angiosperms.

This is quite an archaic way of grouping plants. The kingdom Plantae is usually divided into 10 divisions, listed below, with the groups in the syllabus in bold. Gymnosperms consists of Pinophyta, Cycadophyta and Ginkgophyta. Angiosperms = Magnoliophyta:

  • Anthocerotophyta – hornworts
  • Marchantiophyta – liverworts
  • Bryophyta – mosses
  • Lycopodiophyta – club and spike-mosses
  • Pteridophyta – ferns and horsetails
  • Gnetophyta – 3 extant genera of woody plants
  • Cycadophyta – cycads
  • Ginkgophyta – Ginkgo
  • Pinophyta/Coniferophyta – conifers
  • Magnoliophyta – flowering plants
divisions-for-rhs

Plant Characteristics

Describe and compare the structural and reproductive characteristics of: mosses, ferns, conifers and flowering plants in relation to their adaptation to terrestrial life.

DETAILS OF ALTERNATION OF GENERATIONS AND HAPLOID/DIPLOID STRUCTURES ARE NOT REQUIRED.

I’ve written about these four groups previously, the information about structural and reproductive characteristics is in the first two paragraphs of each blog

  1. Mosses
  2. Ferns
  3. Conifers
  4. Flowering Plants

Brief description of reproductive characteristics:

Bryophytes – have sporophyte and gametophyte stages. Gametophyte is dominant.

Pteridophytes – have sporophyte and gametophyte stages. Sporophyte is typical fern, gametophyte is small and rarely noticed.

Gymnosperm – have male and female cones. Male cones drop pollen which is carried by wind.

Angiosperm – have flowers that may be dioecious, monoecious or hermaphrodite. Usually wind or insect pollinated (but other methods of pollination exist).

1.2 Describe features of plant classification and nomenclature relevant to horticulture.

State the hierarchy of botanical units and explain how and when they are used.

To include: family, genus, species, subspecies, varietas, forma.

To include ONE NAMED plant example for EACH of the above terms showing how it is written.

Family

Have the ending -aceae (many family names were recently changed to conform to this). Plant families are usually named after the biggest or most well known genus in that family. eg Euphorbiaceae, the family that the genus Euphorbia is in.

Genus

Genus is a subdivision of family. The genus of a plant is used as the first part of its binomial name, and is always capitalised. It should be written in italics (or underlined). eg Euphorbia.

Species

Species is a subdivision of genus. The species of a plant is used as the second part of its binomial name and is never capitalised. It should be written in italics (or underlined). eg characias  (as in Euphorbia characias.)

Subspecies

Recommended abbreviation is subsp. but ssp. is sometimes used. Subspecies are written in small italics, but the word subsp. is not. A subdivision of species. Plants within different subspecies but within the same species are capable of interbreeding, but don’t due to geographical separation. eg Euphorbia characias subsp. wulfenii.

Varietas

A subdivision of species, similar to subspecies (and the two terms often overlap) however, different varieties within a species may geographically overlap, unlike subspecies. Recommended abbreviation is var. Varieties are written in italics, but var. is not. eg Malva alcea var. fastigiata.

Forma

If a plant shows uncharacteristic appearance of its species (such as habit or colour) then it can be known as a different form. These differences are usually due to environmental reasons and won’t be passed to the next generation. Recommended abbreviation is f. The form is written in italics, but f. is not. eg Vinca minor f. alba.

Explain the meaning and use of the terms: cultivar, Group, trade designation (selling name), Plant Breeders’ Rights, interspecific, intergeneric and graft hybrids, naming authority.

To include ONE NAMED plant example for EACH of the above terms, showing how it is written.

Cultivar: This is short for ‘cultivated variety’ and refers to plants that have been bred for their characteristics. The names are often chosen as a selling point, for example using somebody’s name, making them a good present for people of the same name. eg Clematis ‘Willy’ (note the cultivar name is capitalized, in single quotes and not italicized. Because of the complexity of cross breeding across species, the species of a cultivar is only sometimes used.)

Group: If several cultivars are similar, they can be grouped together to make customer selection easier. eg Lilium Darkest Red Group (note the group is capitalized, not italicized, and not in quotes.)

Trade designation: Cultivar names cannot be legally protected. If a plant breeder wishes to keep sole legal rights to a plant, then he/she uses a trade name. This a commercial synonym that is legally protected. eg Rosa FASCINATION = Rosa ‘Poulmax’. (note: the writing method for ‘Fascination’ changes, sometimes it is in quotes, like a cultivar; other times it is in square brackets. The correct notation is all in capitals, not italicized, not in quotes, often in a different font.)

Plant Breeders’ Rights: Breeders using a Trade designation have Plant Breeders’ Rights which are recognised internationally. If you own the rights to a cultivar, it cannot be bred by anyone else without your permission. If somebody buys one specimen of your cultivar, you still have exclusive rights to all propagation material of that plant: seeds, cuttings etc.

Interspecific, intergeneric and graft hybrids: Unlike with animals, plants can be bred across species and genera. Plants of different genera can, in some cases, be grafted together, occasionally this will lead to a mixing of cells where the scion and the rootstock meet, this is not a true hybrid. It is also known as a graft chimaera.

examples

  • Interspecific hybrid –  Mahonia × media (bred from Mahonia lomariifolia and Mahonia japonica, note the ‘x’ in the middle and new specific epithet.)
  • Intergeneric hybrid× Cupressocyparis leylandii (bred from Cupressus macrocarpa and Chamaecyparis nootkatensis, note the ‘x’ at the beginning and the genus which is a combination of the parents’).
  • Graft hybrid – +Laburnocytisus ‘Adamii’, (a graft hybrid between Laburnum and Cytisus, note the ‘+’ at the start and genus which is a combination of the parents’.) This graft contains flowers of Laburnum and Cytisus (ie both yellow and purple) but also flowers that are a pinky colour, a mix of the two.

Naming authority: The International Cultivation Registration Authority is a naming authority, responsible for seeing that cultivar names are not duplicated.

State the significance of the ICN (The International Code of Nomenclature for algae, fungi and plants) formerly ICBN (International Code of Botanical Nomenclature) and the ICNCP (International Code for Nomenclature for Cultivated Plants) in the naming of plants.

The ICN (The International Code of Nomenclature for algae, fungi and plants) A code that governs plant discoveries in the world – ensuring that plants aren’t given different names by different discoverers, or that already named plants aren’t given new names without reason.

International Code of Nomenclature website Contains complex set of rules to standardise naming and classification eg changing all plant families to end in -aceae, Compositae > Asteraceae.

ICNCP (International Code for Nomenclature for Cultivated Plants) – a code that governs the naming of newly created cultivars.

Cultivated Plant Code

(For more information about the latest ICNCP, there’s an interesting article on Gardening Wizards, here)

Explain the reasons for name changes: reclassification (scientific research, new discovery), changes in nomenclature (rule of priority), incorrect identification.

To include TWO NAMED plant examples for EACH.

Reclassification (scientific research, new discovery)

  1. With advances in DNA technology, African Acasias were found to not be related to Australian Acasias. Australian Acasias have kept their name, while African have become Vachellia or Senegalia.
  2. Coleus became Solenostemon, but was then found to be part of the Plectranthus genus. Plectranthus scutellarioides used to be Coleus blumei.

Rule of priority

This is where a plant is discovered to have been named previously, and its old name is found on record. When an existing name is discovered, the plant should revert to this name, but occasionally, if the new name is far more familiar it will be kept.

  1. Platanus ×acerifolia was the name of the London Plane, but this name was recorded in 1805 and it was discovered later that an earlier name of Platanus ×hispanica had been recorded in 1770. Therefore Platanus ×hispanica became the official name.
  2. Festuca subgenus Schedonorus was moved to the genus Lolium and its name became Lolium subgenus Schedonorus.

Incorrect identification

Sometimes a name change is due to a simple mistake, when one plant becomes mixed up with another.

  1. Archontophoenix cunninghamiana was for a long time incorrectly sold as Seaforthia elegans.
  2. Syzygium australe was often sold as Syzygium paniculatum

 Explain how plant names can indicate: plant origin, habitat, commemoration, colour, growth habit, leaf form.

To include TWO NAMED plant examples for EACH. 

It is often the plant species that indicates origin, colour etc, but not always (see below). The Latin will only refer to one characteristic (when Latin plant names were first used, botanists tried to include every characteristic, leading to ridiculously long names, then Linnaeus reduced it to two).

Plant origin: Mahonia japonica (Japan), Arum italicum (Italy)

Habitat: Clematis alpina (alpine plants), Pinus sylvestris (wood or forest)

Commemoration: Photinia fraseri (John Fraser1750-1811 nurseryman), Weigela (Christian Weigel 1749-1831 German botanist)

Growth: Briza maxima (large or largest), Vinca minor (smaller)

Habit: Cotoneaster horizontalis (growing horizontally), Phlomis fruticose (shrubby)

Leaf form: Acer palmatum (palmate leaves), Ilex aquifolium (pointed leaves)

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Schachen Alpine Garden

landscape  3

Schachen Landscape

Open four months of the year and accessible only on foot, the Schachen Alpine Garden contains plants from all over the world. As can be seen in the photos, Schachen is often foggy, and despite being surrounded by the Alps, we barely saw them.

Alpine plants have a few conditions in common no matter where they are from; they have to cope with extreme cold (Schachen is often covered with snow), a short growing season, high winds, and a lack of rain. Alpine plants are mostly small and low growing, this enables them to flower in the short time when the conditions are favourable and keep below the high winds.

Anthyllis vulneraria 2

Anthyllis vulneraria

 

A number of plants had an ability to repel water and hold it in droplets above the leaves, I think this is a way of protecting them when covered in snow, stopping the leaves from being damaged. (see photos below)

Due to the mix of rock types on the mountain, the soil is very varied, with alkaline and acid soils side by side. This means that acid loving and alkaline loving plants that would never normally grow together, do. For example, this wild Clematis alpina (alkaline) and pine tree (acid). (see below)

Clematis and pine

Clematis alpina growing on a pine

Many of the pine trees on the mountain are growing right out of the rock (see photos below). In autumn animals bury seeds in the rock to serve as food stores for the winter. Many of these seeds are forgotten, and then germinate.

The photo below is of an unusually shaped Campanula, nothing like the normal bell-shaped flower. Because of its shape it is known as devil’s claw.

Campanula

Devil’s Claw Campanula

Cows feed on the vegetation on the mountain. As it gets warmer, and the cows eat all the vegetation lower down, they are moved up higher. This can cause problems, because the cows will eat almost everything but Rheum (a genus containing rhubarb) because it is poisonous. As a result, the Rheum starts to take over, so there is a problem with this turning the mountain landscape into a monoculture. Rheum is the large-leaved plant in the photo below.

Mosses and lichens were in abundance in Schachen.

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Lichen growing on pine tree

Wild orchids grew on the mountain also.

My favourite two photos from the trip:

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Thistle flower

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Red spotted bug

landscape  5.JPG

Schachen Alpine Garden

 

 

Plant Families: Araceae (aka Aroids or Arums)

Zantedeschia Inflorescence

Zantedeschia Inflorescence

A Few Basic Facts

  • Aroids are monocots in the family Araceae (aka arum family), in the order Alismatales. Most other families in this order contain tropical or aquatic plants, eg Hydrocharis and Saggitaria.
  • Araceae has 104-107 genera. The largest genus is Anthurium with over 700 species.
  • Location: Latin American tropical regions have the greatest diversity of aroids, however, they can also be found in Asia and Europe. Australia has only one endemic species – Gymnostachys.
  • Habitat: Aroids can be aquatic (water), epiphytic (air) and terrestrial (ground). Most are tropical, but there are also arid and cold loving aroids.
  • Distinctive features: All have an inflorescence (a structure containing a group of smaller flowers) which consists of a spadix (always) and a spathe (sometimes).
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Aroid Flowers

  • Aroids can be hermaphrodite (each flower is both male and female), monoecious (male and female flowers on the same spadix) or dioecious (male and female flowers on completely different plants).
  • This family contains one of the largest flowers (Amorphophallus titanium, the titan arum) and the smallest (Wolffia, duckweed).
  • Some aroid leaf and inflorescence shapes:
Aroid Leaf Shapes

Aroid Leaf Shapes

Leaves

Aroid Leaves

Fruits

Aroid Fruits

Adaptations

Like many tropical families, aroids have evolved a number of adaptations to stay healthy and propagate. Some examples of adaptation:

  • The spathe protects the flowers and in some cases is used to trap insects for pollination. It is not a petal, but a modified leaf. Many spathes turn green and photosynthesize after flowering has finished.
  • Aroids have different types of roots adapted to their purpose. They have different adventitious roots  for climbing, attaching to rocks or taking in water.
  • Many tropical species have shiny leaves to deter the mosses and lichens that grow in abundance in the rainforest.
  • Smell is used by many species to attract pollinators. The smell of rotting meat, fungi and excrement is used for flies and beetles. Fragrant scents are used to attract bees.
  • In many species the spadix actually heats up and can reach 25°C, even in near freezing conditions. This increases the release of smells to attract pollinators. The heat also makes visiting insects more active.
  • Aroids that want to attract flies and beetles often have a warty, hairy, twisted appearance, with dark colours. This is to mimic the effect of dead animals, fungi or excrement.
  • In some species, leaves may change shape from juvenility to adulthood – changing from variegated to unvariegated, pale red to green, or altering the number of lobes of the leaf. Colour change may deter animals from feasting on the fresh young leaves by making them look less leaf-like.
  • Most species in Araceae have tubers or rhizomes, this means a damaged plant has the food storage and ability to grow new shoots from many points beneath the ground. Some aroids have other means of vegetatively propagating themselves, such as bubils and offsets.
  • A number of aroids are poisonous, some are edible. Aroids have evolved poisons in some species as protection. Those that are edible did not evolve to be eaten by us, rather we have evolved to be able to eat certain plants.

Reproduction

IMG_4023

Male and Female Flowers

Because many aroids are monoecious there is a danger of self-pollination. While self-pollination is easy (a guaranteed fertilisation), it leads to less genetic variety and less ability to adapt to changes in the environment. Aroids are particularly variable plants, in one small area of the Thai Peninsula 22 distinct varieties of the plant Aglaonaemia nitidum f. curtisii were found. However, in order to achieve this variation, the plant needs to cross pollinate reliably. It does this by being protogynous, meaning the female flowers on an inflorescence ripen first and then later male flowers produce pollen.

The Generic Process for Monoecious Aroids

A beetle, fly or bee (hopefully covered in pollen) is attracted by the scent given off by the heated spadix. The insect flies around inside the spathe, lands on the slippery surface and falls into the gap between the spadix and spathe. At this point only the female flowers are mature, and the  insect, made more active by heat from the spadix, moves about bumping into the flowers and depositing the pollen. Now, the insect has fulfilled the first part of its function, the aroid would like it to pick up pollen from the male flowers. However, the male flowers will not ripen for a day or so yet, so the insect needs to be held hostage. The slippery spathe ensures that the insect can’t escape, it is given sustenance in the form of nectar. Once the male flowers are ready and producing pollen, the slippery surface of the spathe breaks down, allowing the insect to escape. As it flies away it bumps into the male flowers, picking up more pollen to take to the next plant of the same species that it comes to.

Two Specific Examples of Monoecious Reproduction

Philodendron auminatissimum: Sometimes the pollinating insect can outstay its welcome, perhaps damaging flowers or laying eggs. This Philodendron has overcome the problem by shrinking the spathe after the male flowers have become active. This means that the beetle must leave or become crushed.

Arum nigrum: This arum doesn’t trap visiting flies, it merely confuses them. The hood of the spathe hangs over the spadix, obscuring the  sunlight, and there are translucent marking in the base of the spathe. When a visiting fly tries to escape, it heads for the light, but this just guides it deeper into the spathe. This leads to panicked and more active movement, ensuring pollination.

Arum nigrum

Arum nigrum

Reproduction in Other Aroids

In dioecious aroids the female flowers are found on a different plant to the male flowers, so a genetic mix is guaranteed. Not many aroids are dioecious, but a few species of Arisaema are.

A few aroids are even paradioecious and change gender to suit circumstances.

Hermaphrodite aroids are similar to monoecious ones, the male and female parts on each flower mature at different times so self pollination cannot occur.

Habitat

Arid

For the most part, arid aroids have not evolved the typical shrunken leaves and thickened cuticle of other desert plants. Instead they tend to grow under trees and bushes and at the base of rocks where a damp, shady microclimate allows them to survive. They have unusually lush foliage for arid plants. This would make them a target for being eaten, but they have dealt with this by producing harsh toxins and needles of calcium oxalate that pierce and poison the throats of animals. Animals know to stay well clear of aroids.

Some Examples

Dead Horse Arum

Heliocodicerous muscivorus

Heliocodicerous muscivorus: This is called the dead horse arum. It has an inflorescence 35cm long and wide. It grows in the shelter of rocks on a few islands on the Mediterranean. It is pollinated by either flies or beetles and grows where sea birds have their colonies at nesting time. Sea birds live in a mess of rotting fish and eggs, dead chicks and excrement, which attracts the flies/beetles. The arum must then compete with the smell of these, in order to attract those same insects for pollination. It mimics the dead not only in smell, but also by looking like the corpse of part of a horse, complete with tail. Visiting insects find themselves falling into where the ‘tail’ is and becoming trapped by the slippery walls. Many insects lay their eggs inside, although any maggots that hatch will likely starve to death. The insects are held for two to three days and are fed by nectar.

Note: It’s worth looking at photos of the dead horse arum, my painting doesn’t really do it justice.

Sauromatum venosum: This is the called the voodoo lily because it has the ability to flower without soil or water, using only the energy stored as starch in the corm. It smells rotten.

Stylochaeton lancifolius: This aroid has flowers and fruits half buried in the ground. I have been unable to find information about why this is. My suspicions are:

  1.  It is pollinated by animals that are close to the ground. This can be seen in Aspidistra flowers, pollinated by slugs and snails. The flowers grow on the ground, under the leaves.
  2. Being submerged provides a little protection, even if eaten or stepped on, the Stylochaeton still has half a flower remaining.
  3. The fruits are eaten by something small. Having eaten the fruit, the seeds can be dispersed in the faeces.
Stylochaeton lancifolia

Stylochaeton lancifolia

Tropical

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Rainforests are dense, shady, and teeming with aggressive life. Animals, plants, fungi and bacteria are locked in a constant arms race. Consequently aroids have developed strong poisons, shiny leaves and the ability to climb to cope with some of these problems. In the tropics, latitudinal diversity (a wider variety of organisms that occurs close to the equator) means that it may be many miles through dense forest between plants of the same species. For this reason, aroids use very strong, and often unpleasant, smells to attract the right kind of insect.

A tropical rainforest has distinct layers and aroids grow in each of these. There are terrestrial aroids growing in the ground and epiphytic ones that climb into the canopy.

Climbers and epiphytes have only aerial, adventitious roots. There are two types: those that are sensitive to light and make for dark crevices where they can grip, and those that are sensitive to gravity and hang down from the plant in order to soak up rain and humidity.

Terrestrial Examples

Deiffenbachia grows in the Americas, while Aglaonema is native to Asia, they are both highly variable, but virtually indistinguishable from one another. This is an example of convergent evolution. Both contain toxins as a defence; Deiffenbachia is commonly known as dumb cane, because the if eaten, it causes the throat to swell, so that speech is impossible.

Ag 2

Aglaonema and Deiffenbachia – both highly variable, but in similar ways

 

Amorphophallus: This is a genus of tropical and subtropical aroids, native to Asia, Africa and Australasia. They attract flies and beetles by giving off the smell of rotting meat. Unusually, Amorphophallus species only put out one leaf or one inflorescence at a time, one a year. The single leaf is highly divided.

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Some Amorphophallus inflorescences

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Single, highly divided leaf of Amorphophallus

Some species in this genus also have white patches on the stem, these are to mimic lichen growing on trees and serve to protect them from stampeding elephants. When tramping through the jungle elephants have learnt to avoid trees, which are usually covered in lichen. Amorphophallus would be very easily damaged by an elephant, so by looking a bit more like a tree they can fool the elephant into avoiding them.

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Lichen mimicking stem

Epiphytic Examples

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Monstera

Monstera: These are one of the few plants to have holes in their leaves. Recent research shows that leaves with holes benefit in shady areas because the light coming through the trees is often dappled. By having holes in their leaves, Monstera cover a larger area with the same amount of leaf (so the same amount of energy used to make it) as a smaller leaf without holes. This allows the plant to take advantage of any sunlight that gets through the canopy.

Anthurium punctatum: This is an aroid from Ecuador. It has formed a symbiotic relationship with ants. It has nectaries away from the flowers because it is not trying to attract pollinators, but protectors. The ants set up home in the Anthurium and guard it from animals and insects that may eat it. However, in this Anthurium the ants are particularly aggressive and keep away pollinators also. The ants also secrete an antibiotic substance called myrmiacin, which is antibiotic and protects the ants from moulds and bacteria that might cause disease. However, this substance prevents pollen tube formation needed for the plant to be fertilised. These two barriers to pollination mean that the species can only propagate itself vegetatively.

Philodendron: This is a diverse genus. Plants can be epiphytic, hemiephytic or (occasionally) terrestrial. Hemiepiphytic means that the plant spends part of its life-cycle as an epiphyte (in the air). It may start off on the ground and then wind its way up a tree, then let its original roots die back. Or it may start as a seedling in the branches of a tree and a root will trail its way to the ground.

Philodendron bipinnatifidum

Philodendron bipinnatifidum

Temperate Woodland

Arisarum proboscideum

Arisarum proboscideum

Arisarum proboscideum: aka the mouse plant. This is a woodland aroid, native to Spain and Italy. It has flowers like little mice. The ‘tails’ of these give off a mushroomy odor, that attract fungus gnats for pollination. The flowers have a spongy white appendage inside the spadix that looks like a mushroom to complete the deception. Fungus gnats often lay their eggs in the flowers, although the maggots won’t live to adulthood.

Aquatic

As I have blogged before, plants never evolved much in water. This means that all aquatic plants have evolved on land and then evolved again to cope with life in water. Some problems faced are – damage to flowers and leaves due to water currents, lack of access to pollinators, water blocking out light, lack of oxygen (leading to rotting roots), and the heaviness of water (800 times as dense as air) putting pressure on foliage.

Some solutions to problems:

  • Aerenchyma:  these are gas filled cavities that improve buoyancy and oxygenation.
  • Fish shaped foliage: these offer less resistance to water currents, so less damage occurs.
  • Larger surface area in relation to volume: ie filmy leaves. This increases photosynthesis  eg Cryptocoryne
  • Roots: These are not needed to transport water, since it can be taken in by all parts of the plant. However, roots are used to anchor the plant and stopped it being carried away by currents. eg Jasarum steyermarkii
  • Reproduction: Many aquatic aroids find it easier to spread vegetatively rather than by flowering, in order to avoid flowering problems.

An Example

Pistia stratiotes 2.JPG

Pistia stratiotes: This is the only floating aquatic aroid, growing in swampy deltas in India and West Africa. It is adapted to staying still in fast moving currents, and has found the balance between sinking and blowing away.  The inner tissues have aerenchyma and the outer surfaces are ridged, velvety and with dense covering of hairs. This makes it unable to sink, and water repellent. Feathery roots act as an anchor. It has tiny flowers in a protective hairy spathe.

Pistias form a dense mat on the surface of the water, and can create mats of 15m wide. This makes Pistia something of a weed, causing problems to the ecosystem because the water underneath is deprived of light.

However, Pistia is not only harmful, some ecological benefits:

  • The darkness caused by the Pistia mats has led to the evolution of blind elephantnose fish, which live beneath the mats. They hunt by electricity and have well developed brains and learning abilities.
  • Birds and animals often make the floating island their home.
  • Pistia can purify stagnant water.

 

Note: outdoor photos are mostly taken in Ecuador and indoor photos mostly from Wisley Gardens.

 

RHS Level 3 Planning, Construction and Planting – UNDERSTANDING SURVEY TECHNIQUES AND GARDEN PRINCIPLES

  1. Understand the historical development of garden design styles.

    1.1 Describe representative characteristics of the following garden design styles: Moghul, Moorish, Medieval, Renaissance (Italian, French and Dutch), English Landscape, Victorian, Edwardian, Japanese, Modernist, Contemporary.

DATES

STYLE

EXAMPLES

MOGHUL

(Afghanistan, Pakistan, India)

 C 16-19th

Formal, symmetrical, water – channels and pools, terraces, avenues of Cyprus, scented flowers. 4 types: palace, tomb, waterfront and terrace.

Taj Mahal, Agra

MOORISH

(Spain, Portugal, S. Italy, France)

 C 8-15th

Water and shade used to cool gardens. Gardens divided into four. Fountains and ponds, ceramic tiles, carved stones, hedges, containers, fragrant flowers. Cyprus, Sycamore and Citrus.

Maria Luisa Park, Seville

 MEDIEVAL

 C 12-15th

 Food production – orchards, herbs, medicines and vegetables. Walls, fragrance, wells, turf seats, arbours, grassed dancing, mounts to view. Pleached limes.

Alfriston Clergy House

 ITALIAN RENAISSANCE

 C15-16th

Parterres. Dramatic views, spectacular fountains and cascades, woodland, orchards, herbs, levels. Inspired by Romans and ancient mythology.

Villa Lante

FRENCH RENAISSANCE

 C15-17th

Parterres. Acute angles, ornate statuary, fountains, rigid symmetry, canals, views, focal points and cascades at the end of every vista. Terraces and grottoes.

Luxembourg Gardens

DUTCH RENAISSANCE

 C15-17th

Parterres. Rectangular spaces divided to squares, leafy walks, arbours, fountains, mazes, bulbs. Buxus hedges. Helianthus, Papaver and Rosa.

ENGLISH LANDSCAPE

 1720-80

Idealised version of nature, inspired by paintings. Classical. Lakes, rolling lawn, grove of trees, temples, Gothic ruins.

William Kent, Lancelot Capability Brown

VICTORIAN

 1837-1901

Glasshouses and conservatories leading to overwintered tender plants. Carpet bedding, new plants from abroad – Dahlia, Aster, Impomea, Zinnia. rockeries, parterres, arboretum.

Sir Joseph Paxton, Cragside, Northumberland

EDWARDIAN

 1901-1910

Hedges, Terraces, sunken, pergolas, cottage garden styles

William Robinson, Lutyens +Gertrude Jekyll, Reginald Bloomfeld

JAPANESE

 600AD

Borrowed scenes, asymmetry, moss gardens, bonsai, miniature landscapes, fish, cloud pruning

Nanzen-ji

MODERNIST

 1800  popular 1930

Water, geometric, asymmetry, crisp + clean, planting in one part. large horizontal landscaping – stone, wood, concrete, cement, plastic.

CONTEMPORARY

Last ten years

Grasses, sunken LED lighting, simple, bold, architectural planting, repetition of plants, hard landscaping innovative and central to design, natural looking materials eg distressed metals, stone, sustainable materials.

Difference between Modernist and contemporary styles

Firstly, Modernism is a specific movement that started in the 1800s whereas contemporary is simply what is happening now. Modernism occurred at a time of the Industrial Revolution when form followed function – how well it worked mattered more than how it looked. As a result the garden style was simple with no fancy details. Contemporary tends to use a similar ethos (simplicity, functionality) but it also tends to reflect our recent interest in sustainability using recycled materials more. Plus it is influenced by our desire for more natural looking settings, so functional metal is a common material for both Modernist and contemporary, but distressed metal looks more natural and so features only in contemporary. Recent advances in LED lighting are also made use of in contemporary styles. Contemporary gardens often follow current fashions such as willow fencing, decking or insect habitat boxes.

  1.  Understand how to conduct a site appraisal and interpret the results

    2.1 State the main factors to be assessed for an overall site appraisal.

    2.2 Review the advantages and limitations which site factors may impose on garden planning and layout, to include accessibility for disabled users.

Information about the site to be collected at site appraisal and advantages and limitations:

Microclimate – caused by walls, buildings and plants altering the climate over a tiny area. Can provide planting opportunities (eg tender planting in sheltered corners) or planting restrictions (limited planting possible at the base of a Taxus hedge). Hard landscaping is also affected by microclimate (eg moss and algae forming on decking in shady areas).

Orientation – The direction the garden faces in affecting sun, shade and wind  (north=cold and shady, south=warm and sunny) in turn affecting the positioning of features (walls shouldn’t block sun, patios may need shade/sun) and plants (shade loving, tender plants needing specific aspect). Similar to microclimate.

Access – to garden from road, from house to garden and around garden. Relevant for both work in the garden and garden users. Disabled users – question whether existing hard landscaping is safe and convenient for use, whether ramps, handrails and so on are adequate. Children – are there safety risks, such as ponds? For gardeners and landscapers – will work be limited or more costly due to difficult access?

Climate – the long term weather patterns of an area,  includes prevailing wind (from somewhere warm or cold), temperature (varies according to urban/rural setting, closeness to sea and topography) and average rainfall. Both plants and features are affected by climate . Similar to orientation and microclimate, important to think about what plants will thrive best, what hard landscaping materials will need the least maintenance in that climate and about how the garden owners will want to enjoy the garden – eg a cold, wet climate is not ideal for an outdoor swimming pool.

Contours – the varying heights within a garden. Levelling may be necessary for patios or to get rid of frost pockets. Drainage and erosion may be a problem. Levels can add interest. (see next blog for information about how to ascertain levels). Disabled users may have particular problems with slopes or stairs. Steep slopes can limit building access and maintenance (eg lawnmowers struggle with slopes). Sunken areas and steps can create views and interest.

Existing features – their condition, what needs to be kept, existing colour scheme and style. See access. Particular features may be used to build a design style around – for example a beautiful Victorian wall can inspire a Victorian garden.

Services – drains, electricity, water pipes. Overhead and underground services to be recorded. Overhead power lines may restrict use of machinery, underground pipes may be a problem when laying drainage or building swimming pools.

Soil – pH, textures, structure, top soil depth, soil pans, drainage, nutrients, rubble and contamination content. Planting might be limited eg only calcifuges or bog plants. Topsoil may need to be imported.

Existing vegetation – their condition and interest, privacy and wildlife to be considered, Tree Preservation Orders. With TPOs it may not be possible to cut down a large, imposing tree, birds nesting may limit timing of hedge cutting/removal. For disabled users – consider whether soft landscaping is easy to care for, for children – whether existing plants are harmful – if ingested, toxic sap (eg Euphorbia)

Dimensions – size and shape of the garden affects types of features and plants used. Designing for awkward shapes can lead to innovative use of hard/soft landscaping. Size and shape of garden affect design (eg a narrow garden may use diagonal patterns, lawn size and hard landscaping to increase feeling of width, a small garden needs hard and soft landscaping in proportion to the garden size, a large garden can be divided into different ‘rooms’ and styles). Opportunity to use unusual shapes to create interest or use landscaping to make an uninteresting shape more unusual.

Legislation – TPOs, conservation areas, planning regulations, boundaries (height of walls etc), Hedgerow Regulations all can restrict what change are possible. See existing vegetation.

Exposure – how much a garden is open to the elements and affected by wind or salt in coastal gardens. Relevant to plant selection (certain plants survive better in exposed areas) and seating (people don’t usually want to sit in a high wind). Wind breaks (hedges or walls) can be put into design. In a sheltered garden tender plants may be grown and in an exposed garden hardy plants will be needed.

Altitude – affects the range of plants grown, higher altitude=low temperature and more exposed. See Exposure.

Views – what surrounds the garden. Borrowed views can be used to create a larger garden or it may be necessary to hide ugly views by screening.

External factors – includes views, causes of microclimate (eg large buildings = shade), wildlife. See views, climate, legislation and microclimate.

  1. Know how to develop a client brief

    3.1 Identify the information which needs to be gathered from the client, to include: likes and dislikes, aspirations, functional requirements (e.g. utility, play area for children, restricted mobility), ornamentation, relaxation, entertaining or food production, degree of maintenance and budget.

Questions that can be asked to clients (taken from a number of client questionnaires on the internet, garden design websites are good for this).

What are your personal preferences?

  • What do you like and dislike about your garden?
  • What colours do you like?
  • Any specific styles you like (eg Alpine or formal)?
  • Any specific plants you would like?

What mood would you like for your garden (mark all appropriate)?

  • Calming
  • Private
  • Fragrant
  • Colourful
  • Tropical
  • Practical
  • Wild

What do you use your garden for?

  • Do you like entertaining?
  • Have any sports hobbies (football, swimming)?
  • What time of the year will you most use your garden?
  • What time of day?

Which features would you like (mark all appropriate)?

  • Water feature
  • Vegetable patch
  • Fruit
  • Herbs
  • BBQ
  • Lighting
  • Children’s play area
  • Parking
  • Compost

Do you like gardening?

  • How much time will you be able to spend on the garden a week?
  • Will you be hiring a gardener?
  • Any specific jobs you hate (eg Mowing the lawn, raking leaves)?

Who is the garden for?

  • Do you have children or pets?
  • Anyone with any disabilities or special needs to use the garden?

Are there any specific problems you would like solved (mark all appropriate)?

  • Bad drainage
  • Lack of privacy
  • Noise
  • Unpleasant views
  • Pests (badgers, rats and rabbits)

What is your budget?

3.2 Describe how to record relevant data using a client questionnaire, audio and visual methods.

Collect information from client by:

  • Using a questionnaire (may be online or in person)
  • Email
  • Using a digital audio recorder
  • Taking photographs (if an iPad is used, redesigning can be put straight onto a photograph)
  • Sketches

This leads to a Concept Plan that shows problems and applies solutions. In addition to this the site appraisal provides information on the dimensions and details of the garden which is used to draw up the various design plans.

4. Know a range of basic survey techniques

4.1 Describe the linear surveying of a site using appropriate equipment to include tapes and automatic levels.

Definitions

  • Linear surveying – Measuring distances between points on parts of the earth’s surface. In a garden survey this would include measuring the size and shape of hard landscaping (eg walls and fences), boundaries and plants (eg trees) that are to be kept in the design.
  • Datum – line or level surface to which all heights are referred.
  • Reduced level – level above or below the datum point.
  • Line of collimation – line of sight horizontal to the ground.

Equipment

  • Tapes – measuring tapes. Lots of clear info here – Linear Measurement Taping.
  • Automatic levels – a device mounted on a tripod used to measure levels. Used with a staff.
  • Dumpy level – similar to automatic level, slightly different mechanism Wikipedia page.
  • Theodolite – a precision instrument for measuring angles in horizontal and vertical planes.
  • Electronic distance measurement device (EDM) – a hand tool that accurately measures distance by sending a pulse of light to a surface.

Methods

  • Triangulation – using two known points to determine the position of a third, unknown point by measuring the angles and distance.
  • Trilateration – using the geometry of circles, squares and triangles to determine, record and map the position of features.
  • Offsets – marking the position of a number of features, measured from a straight line (a measuring tape).
  • Clock method – mark central point and walk round in a circle recording features.
  • 3:4:5 Triangle – used to find a right angle, useful for measuring, especially offsets. Beautifully simple explanation here.

Excellent website for how to conduct a linear survey, how to set up levels and how to produce contours and longitudinal sections here – Linear survey.

 4.2 Describe the surveying of a site to record variation in levels using automatic level and staff.

Websites

4.3 Interpret survey measurements from standard documentation.

4.4 Produce scale drawings using survey data, including the correct use of graphic symbols, scale and nomenclature.

Types of Plan

Designer’s Plans

  • Location plan (marking where site is on a map)
  • Zone map (shows soil type, microclimate etc)
  • Site survey
  • Concept plan (shows problems and solutions)

Plans for Client

  • Sketch design
  • Final design
  • Sketches, elevations and perspective drawings

Plans for Construction

  • Construction details
  • Hard works layout plan (BSI graphics, structures and levels)
  • Services
  • Planting plan
  • Setting out plan (dimensions, measurements and offsets)

Equipment

  • Scale ruler
  • HB and 2H pencils
  • Eraser
  • French curves
  • Compass
  • Drafting pen

Websites

How to Draw a Garden Plan

Two websites from which you can download (for free) garden design symbols, or just see the symbols and get an idea of what there is:

5. Understand how site characteristics may influence garden design 

5.1 Explain the influence of the following on a choice of design : altitude, orientation, aspect, changes in level, pollution, soil type, soil depth, soil pH, soil water content, views, screening, degree of exposure or shade, microclimate.

5.2 Explain how a given design may be used to enhance the attributes and offset the limitations imposed by the site.

(note: these questions cross over with 2.1 and 2.2 covered in the previous blog, however, I’ve elaborated on them here.)

Altitude

Problems with high altitude:

  • Much shorter growing season.
  • May have midsummer hail and frost.
  • Intense sun, high winds and drought.
  • Rocky alkaline soils or forest-shaded acidic soils.
  • May be nutrient deficiency due to leaching.
  • Heat is slower to build and quicker to dissipate.

Solutions to problems:

  • Alpine plants
  • Terracing
  • Mulching with organic matter to improve soil

Orientation

Design adaptations for South facing gardens (sunny):

  • Sun loving plants – Mediterranean or succulent – styles led by planting
  • Pale hard landscaping
  • Providing shaded areas for seating
  • Irrigation for plants
  • Water features can provide sense of cool

Design adaptations for North facing gardens (shady):

  • Shade loving plants
  • Problems with growing grass – keep lawns small or use a moss lawn
  • Algae forms on decking in the shade, use brick or stone
  • Use mirrors and reflective surfaces to increase light
  • Use pale flowers and bright colours
  • Position seated areas to make the most of the sun
  • Avoid shading more areas with large trees or high walls

East facing gardens have early morning sun that can cause frost damage on some plants, to avoid this, position variegated or tender plants carefully to avoid early morning sun. Camellias are especially susceptible.

Aspect

Note: Orientation and aspect are often considered to be the same thing, but aspect can also include shade and shelter (eg a sheltered aspect). Sheltered gardens often suffer from shade, this is covered under North facing gardens above.

Changes in Level

Ways to use existing levels or create changes in level:

  • Steps
  • Sunken areas
  • Raised beds
  • Sunken paths surrounded by walled beds
  • Mediterranean style gardens with split level patios.
  • Tiered multilevel gardens
  • Rockeries
  • Waterfalls

Problems with slopes, solutions:

Pollution

Different types of pollution and solutions:

  • Rain – a rain garden – a planted depression that absorbs water and allows it to flow into the ground rather than storm drains.
  • Noise – walls and thick growing trees or shrubs block sound, running water features and wind chimes cover sound.

Soil Type

Factors to consider and solutions:

  • Soil texture – eg sandy or clay. Affects what plants can be grown and what kind of drainage can be used. Clay soils may benefit from raised beds, sandy from incorporated organic matter.
  • Soil structure – improved by adding organic matter, maybe add a compost bin to a garden with bad soil structure.
  • Topsoil depth – plant choice is limited by shallow soils. Raised beds can solve this.

Soil pH

Acid loving plants – Camellia, Calluna, Kalmia, Erica, Cornus, Acer, Abies

Alkaline loving plants – Geranium, Aucuba, Lavandula, Delphinium, Crataegus

Note: outcome 3 of unit 2 will cover plants for situations more fully

Soil water content

  • Make use of wet gardens with bog plants or ponds
  • Make use of dry gardens with succulents
  • Solve drainage problems with a swale, pipe drainage or a soakaway
  • Solve irrigation problems with a leaky hose

Views

Borrow views from neighbouring gardens and landscapes, creating a connection between plants inside and outside the garden. Hide ugly views with screening – fences, climbers, trees; or distractions – brightly coloured foliage or landscaping that draw the eye.

Screening and exposure

Types of screening:

  • Hedging – Taxus baccata, Ilex aquifolium, Ligustrum ovafolium
  • Evergreen climbers – Trachelospermum jasminoides and Clematis armandii
  • Walls – brick, cement blocks and dry stone walls
  • Fences – woven willow, featherboard and panel fencing
  • Trees – Arbutus unedo and Eucalyptus gunnii

Exposed gardens, problems and solutions:

  • Plants exposed to the elements (harsh winds, sea spray) – hardy plants, thick hedges, walls.
  • Soil erosion – see Changes in Level.

Microclimate

This is linked with aspect and orientation. A garden can contain many subtle (or not so subtle) differences in moisture, shade and shelter and so solutions to those types of climates can also apply on a small scale to the microclimates in a garden.

6. Understand the principles and elements of design

6.1 Explain the principles and elements of design: to include movement, rhythm, scale balance, form, texture, space, colour , proportion, harmony, unity, symmetry, and asymmetry, focal point, borrowed landscape.

6.2 Describe examples of the application of the elements in 6.1 to the design process.

Movement

How the eye moves around the garden, some shapes, patterns, paths and lines create movement. Also physical movement – water, plants.

  • Curves create gentle, restful movement
  • Angles give a sense of restlessness
  • An off-centre focal point can create a sense of movement and dynamism, and invites curiosity
  • See also Form
  • Water in water feature is constantly moving
  • Grasses move in the wind

An article about rhythm and movement

Example: A curving, winding path edged with long grasses (Miscanthus sinensis) would create a soothing, but constant sense of movement. See Piet Oudolf designs.

Rhythm

Using repetition to connect areas of the garden and create unity, also connected to movement, since rhythm is found in the pattern of visual movement.

  • Repeated features – flower colours, hard landscaping, clipped topiary
  • Repeated styles – sweeping lines, geometric patterns, interlocking features
  • Repeated colours – pastels, primary colours, contrasting colours, deep reds and grey foliage

Example: A set of three, large, terracotta pots on a wall filled with identical purple Lavandula angustifolia ‘Hidcote’ bushes, edged with black Ophiopogon planiscapus ‘Nigrescens’. This purple and black colour combination can also be used elsewhere in the garden and the terracotta colour can be repeated in red brickwork.

Scale

Scale refers to the size of the garden in comparison to non–garden objects (as oppposed to Proportion which refers to the size of garden components in comparison with each other), for example:

  • Size of humans in relation to garden (eg paths)
  • Size of garden in relation to house
  • Size of surroundings (eg trees and buildings outside the garden) in relation to garden

Example: A garden surrounded by a wood with large trees needs at least one large tree inside the garden to give a sense of scale. For example an oak woodland would benefit from three Quercus robur inside the garden, spaced to connect the whole garden with the view.

Balance

Balance is an even distribution of visual weight – weight created by colour, colour brightness, landscaping or plant size. Balance is like a very loose symmetry, for symmetry if there is a statue on one side of the garden there should be a statue on the other, whereas a statue in one part of the garden can be balanced with a pergola in another part.

  • No single object should dominate excessively

Example: Three Acer palmatum ‘Bloodgood’s ( that turn bright red in the autumn) are spaced apart on one side of the garden, and can be balanced with a single, larger Cotinus coggygria ‘Royal Purple’, (that also turns red in the autumn) on the other side of the garden.

Form

Form is the habit and shape of plants, different plant shapes create interest, harmony and/or movement

  • Fastigiate form creates dynamic effect.
  • Combine shapes, eg transparent sprays in front of solid colour, weeping shapes with upright.
  • Forms – fastigiate, weeping, columnar, oval, round, spreading, pyramidal.

Example: Closely pruned Buxus domes contrast with upright Euphorbias and sprays of fine textured grasses (see below). There is enough enough interest to make this an enjoyable garden to look at, but enough repetition to unify the garden.

Telegraph Garden at Chelsea

Telegraph Garden at Chelsea

Texture

Texture is determined by leaf size, by light reflected from leaf surface or by comparative detail on hard landscaping. Combined with colour and form, plants can be put together in a way that is striking or subtle. Most designs will use a combination of striking accents in a subtle whole – all subtle can be dull, all striking is exhausting.

  • Light filtering translucence of thin leaves contrasts with reflected light of small leathery leaves.
  • Textures can be fine (small leaves eg Buxus sempervirens), medium or coarse (large leaves, eg Musa basjoo).
  • Mixing textures creates interest, however it’s not good to position fine with coarse, instead use fine with medium, medium with coarse.

Example: (see below) The large variegated leaves of Hosta with smaller, divided, purple leaves of Heuchera.

Chelsea Flow Show

Chelsea Flow Show

Example: Spiky Eryngium giganteum with soft Salvia argentea and fine Stipa (picture).

Space

Space can refer generally to the area to be designed or more specifically to how open an area is.

  • Balancing privacy and shelter with a more open sense of space.
  • Using partially visible areas to create interest– Hahas, large circular holes in walls, hedges, walls.
  • Restraint – reveal a little at a time – eg series of focal points gradually revealed.
  • Different heights can be blocked from view – using hedges or a canopy of trees.

Colour

  • Reds and orange brings warmth and vitality
  • Blues pinks and whites are subdued and cooling, add depth
  • Colours can be used to bring unity – repeating certain colours in hard landscaping and planting
  • Green is used as a foil in garden design, a neutral colour
  • Too much colour variety can be exhausting
  • Use different seasons to explore different colour palettes

ColoursExample: A herbaceous bed at Kew Gardens (see below) uses harmonious colours, reds to yellows.

Kew Gardens

Kew Gardens

Proportion

Proportion refers to the relative size of parts within a whole, how the size of garden components relate to one another.

  • The divine proportion (golden ratio) is 1:1.618, using this as width to length is satisfying to look at.
  • Have a third hard landscaping to two thirds of soft (some styles do not follow this).

Example: Every design on this siteshows very pleasing proportion; paths, pots, hedges and plants all fit together in a satisfying way where no part feels out of place or wrongly sized.

Harmony

This incorporates balance and unity throughout a design so that all parts of the landscape are adapted to one another, forming an agreeable whole.

  • May be colour harmony – using colours that work well together, either complimenting or contrasting.
  • Harmony does not need to be safe and conventional : unconventional, innovative designs can still be harmonious.

Example: Using a limited colour palette, such as burgundy and whites (see below), the fluid planting, and rock and cobble stone hard landscaping create a harmonious whole.

Vital Earth Nightsky at Chelsea

Vital Earth Nightsky at Chelsea

Unity

A thread or theme running through the garden that connects everything together. May be:

  • Colour (see colour, can be in both hard and soft landscaping)
  • Period of history (eg Victorian, Landscape)
  • Style (eg Mediterranean, Japanese)
  • Repeated hard or soft landscaping (eg Buxus hedging)

Symmetry and Asymmetry

The use of mirror image with identical hard/soft landscaping either side of an imaginary line (or not identical for asymmetry).

  • An asymmetrical design can use the golden ratio to establish balance.
  • Symmetrical designs use parterres (four way symmetry).
  • Bilateral symmetry – mirror image split down the middle, eg fastigiate Populus nigra and domed Buxus in a pattern of bilateral symmetry or a Buxus parterre.
  • Radial symmetry – like a wheel with spokes.
  • Approximate symmetry – similar objects and shapes either side of a line, not exact, varying in pattern etc.

Focal Point

An object of interest that draws the eye

  • Water features
  • Statues
  • An architectural plant
  • Hard landscaping
  • It’s important not to over use focal points so a garden becomes cluttered.
  • Remember balance when positioning them (or use symmetry).
  • Focal points work well when partially seen, at the end of a journey through the garden, or when partially obscured to create interest.
Water Feature Focal Point

Water Feature Focal Point

Statue Focal Points by David Meredith

Statue Focal Points by David Meredith

Some more examples of focal points here, here and here.

Borrowed Landscape

Using an attractive view or plant (usually a tree) outside the garden. This can be done by:

A couple of very good books that define and describe concepts such as unity and harmony, and talk about plant combinations, using texture, colour and form:

Odd plants: Ruscus aculeatus

Ruscus aculeatus

Ruscus aculeatus

Ruscus aculeatus, or Butcher’s Broom, is a woodland shrub native to Europe, it has holly-like leaves and bright red berries. However there is a little more to this plant than meets the eye.

Ruscus aculeatus

Ancient Woodland Indicator

Ruscus aculeatus is an ancient woodland indicator plant, this means that its presence suggests a wood is more likely to have been around since before 1600.

How old is ancient? The chosen cut-off date, AD1600, around the time of the death of Queen Elizabeth I, is not entirely arbitrary. It marks the beginning of reasonably accurate estate maps, and also the first known widespread tree-plantings. Any wood known to exist in its present form by that date is almost certainly natural in composition even if it was heavily managed. (passage taken from britishwildlife.com, link below)

It is generally true that the older a habitat the more species it will contain and therefore the greater importance it has in nature conservation. However, it is not always easy to know exactly how old woods are; assessing species diversity is complex and documentation about an area is rarely complete, so alternative methods have been found using plants. Some vascular plants are known to not grow well in secondary woodland, and are often found in woods known to be ancient, so conclusions have been drawn that the presence of these plants suggest an older wood. This is not a foolproof indicator and the plants that show such growth habits are different in different parts of the country and on different soils, however, to botanists who have learned to study the signs, Ancient Woodland Indicators are an important clue to the history of the area.

More detail here

Leaves and Cladodes

Ruscus aculeatus

Ruscus aculeatus

Ruscus aculeatus is, at first glance, a fairly straightforward plant, it has pointed flat leaves, like a small leaved holly, a typical dicotyledon (more information about dicotyledons). However, looking more closely at the leaves, they are a little odd, firstly they are not horizontal to maximise the sun’s rays, they are end on. Secondly, the leaves have no evidence of veins, there is a slight crease down the middle, but not much else about them is leaf-like. Even more curious is that Ruscus is not is dicotyledon at all, but in the asparagus family, a monocotyledon, and so their leaves should be long and strap-like, with parallel veins. The reason these leaves do not conform to expectation of moncot leaves is because they are not leaves at all, but modified stems, stems that are specialised for photosynthesis, known as cladodes. Cladodes also appear in the cactus family.

A further clue that these are stems, not leaves, can be found in the flowers and fruits, which grow right in the middle of the cladodes, something which doesn’t tend to happen with real leaves.

Flower and unripe fruit

Flower and unripe fruit

Ripened fruit

Ripened fruit

There are also other Ruscus species with cladodes, again recognisable by the odd positioning of flowers and fruits. Below is Ruscus hypoglossum, the small protrusion above the fruit is the real leaf.

Ruscus hypoglossum

Ruscus hypoglossum

Family: Ruscaceae and Nolinoideae

Sansevieria

Sansevieria

The asparagus family (Asparagaceae) is one that has changed recently. Previously Ruscus was in the smaller family Ruscaceae, this has now been renamed Nolinoideae and is a sub family within Asparagaceae. Within Nolinoideae are some familar plants – Liriope, Ophiopogon and Polygonatum (Solomon’s Seal), plus a couple of exotic plants – Dracaena and Sanseveria – but it is the less familiar Danae racemosa and Semele androgyna (pictures below) that have cladodes and the resulting flowers and fruit sprouting from these.

Semele androgyna

Semele androgyna Leaf

 

Danae racemosa leaf and flower

Danae racemosa leaf and flower

Danae racemosa flower close up

Danae racemosa flower close up

 

Fasciation

Normal Flower and Fasciated Flower

Normal Flower and Fasciated Flower

Fasciation in plants is a bizarre mutation in the meristem (growing point) leading to flattened flower stems and distorted flowers, fruits and roots. It can also lead to a ring of small flowers surrounding the main flower, this is known as ‘hen and chicks’ and can be seen in some of the Veronicastrum pictures below. The meristem is where cells actively divide in order to grow or create new flowers and leaves, a disturbance to this process can lead to the cell division intensifying and occurring in a haphazard manner, leading to distortion. Essentially the growing point ceases to be a point and instead forms a cockscomb. For many plants this is most commonly noticed with flowers, which then go on to form distorted fruits, but with cacti and ferns it is often seen in the leaves.

Causes

Genetic

In some plants, such as the soybean (Glycine max), fasciation is caused by a single recessive gene. This means that fasciation will only occur if both parents of a plant have that gene and pass it on.

Multiple distorted flowers Veronicastrum 'Fascination'

Multiple distorted flowers Veronicastrum ‘Fascination’

Physiological

Normal and Fasciated Spathyphyllum

Normal and Fasciated Spathyphyllum

In plants without the gene, fasciation is caused by disturbance to the meristem at the time of growth. This disturbance can be caused by

  • Mites or insects feeding on the shoot
  • Fungal, bacterial and viral diseases
  • A sudden change in temperature – eg going from low to high or high to low (especially in Hyacinthus)
  • Zinc deficiency or nitrogen excess
  • Drought followed by heavy watering

Frequently Fasciated Plants

The following plants have exhibited fasciation: soybean, many cacti, ferns, Euphorbia, Prunus, Salix, cannabis, Aloe, Acer, Forsythia, Delphinium, Digitalis, Taraxicum and Syringa.

Artificially Induced Fasciation

In some cases fasciation is seen as a desirable characteristic, it can lead to increased yield in crops due to the enlarged heads, or provide a talking point in ornamental displays. Examples are the maize, Celosia cristata and Asplenium cristata (note the species name ‘cristata’ – cristate is another word for fasciation). To this end, the above conditions can be induced or one of the following methods used:

  • Manipulating the photoperiod (exposure to light)
  • Using susceptible cultivars (see below)
  • Using radiation – gamma rays or ionizing x-rays.
  • Chemical application – growth regulators or polyploidzing agents
  • A cutting or scion taken from a fasciated plant will create a new fasciated plant

Veronicastrum ‘Fascination’ is a cultivar grown for its tendency to fasciate.

Fasciated stem of Veronicastrum 'Fascination'

Fasciated stem of Veronicastrum ‘Fascination’

Veroncastrum 'Fascination'

Veroncastrum ‘Fascination’

Fasciation in Cacti and Other Succulents

Many cacti and succulents are subject to fasciation, although the word more commonly used to describe this state is cristate. More than fifty cacti genera have shown cristation, as well as the succulent families Crassulaceae, Asclepiadaceae and Euphorbiaceae. Some cacti have ‘Cristata’ in the name. Fasciated cacti form ribbon like weaves, or have many divisions. Cristation is often cultivated in cacti, with cuttings used to perpetuate the cristate cacti. It is thought that some cacti species have a genetic propensity to cristation and somatic mutation (genetic alteration caused by environmental factors as described above) leads to the physical changes. Seeds from fasciated stems in cacti often lead to fasciated seedlings, although this is not necessarily true of other plants, Digitalis, when fasciated, does not produce fasciated seedlings.

Mammillaria elongata cristate

Mammillaria elongata cristate

Some more cacti showing signs of cristation

Fasciated Mammillaria compressa

Fasciated Mammillaria compressa

Normal and fasciated Mammilaria

Normal and fasciated Mammilaria

Euphorbia

Euphorbia

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 Fasciation in Ferns

Several ferns are especially cultivated to be cristate, such as Dryopteris affinis ‘Cristata’ or Asplenium cristata

Asplenium cristata

Asplenium cristata

 Additional information and pictures:

Plant Divisions: Flowering Plants

Leaf Variety in Magnoliophyta

Leaf Variety in Magnoliophyta

Plants in the Magnoliophyta Division may also be called Angiosperms or flowering plants, they include grasses, palms, oak trees, orchids and daisies. Magnoliophyta is the only division that contains plants with true flowers and fruits, and all plants in this division use those flowers and fruits to reproduce. It is not known exactly when flowers first appeared, but definitely by 125mya and probably as far back as 160mya.

Flowers have proved to be an extremely successful adaptation, and despite its recent appearance, Magnoliophyta is by far the largest and most diverse plant division with over 250,000 different species and 500 families. (For comparisons to other divisions and their sizes see here)

Leaf Variety in Magnoliophyta

Leaf Variety in Magnoliophyta

Flowers

In Magnoliophyta, flowers replaced the cones of more primitive plants, as a means of reproduction. Some flowers are brightly coloured, have a scent or produce nectar in order to entice animals to pollinate them, but others use wind or water and, having no need to draw attention, are barely noticeable.

Flower Variety in Magnoliophyta

Flower Variety in Magnoliophyta

Flower Variety in Magnoliophyta

Flower Variety in Magnoliophyta

Fruit and what that really means…

All plants in this Division produce fruits of some kind, even though what they produce may not be easily recognised as fruit. The botanical definition of a fruit is a matured ovary (the ovary is the female part of the flower that contains the ovules which become the seeds once fertilised), this includes peppers, tomatoes, aubergines, nuts, peas, wheat grains, but not apples or rhubarb. There is another meaning for the word fruit, which is culinary and refers to a sweet part of a plant that is eaten, this is the more familiar term and includes rhubarb and apples, but not tomatoes and nuts, etc. ‘Vegetable’ is only a culinary term, referring to parts of a plant used in savoury cooking, it may refer to any part of the plant: leaves (lettuce) flower buds (broccoli), stems (celery) or roots (carrots) and has no botanical equivalent.

Classification

Being such a large and interesting division means that the classification of Magnoliophyta has received more attention and undergone more changes than any other division.

How Many Flowering Plants Are There?

It was believed for some time that there were over 400,000 flowering plants, but it turns out that many species of plant (not known as yet how many) have actually been named twice or even three or four times. The binominal naming system (using two Latin names, eg Helianthus annuus) was designed to make plant naming international and straightforward, but with people all over the world discovering and naming plants and no comprehensive way of cross referencing them, we have ended up with a lot of confusion. Now, partly due to the international power of the internet, serious attempts are being made to work out how many actual species there are and to remove duplications. The Plant List is a collaboration between a number of botanical gardens around the world and has an impressive online collection of these names.

DNA Alters The Family Tree – Cronquist to APG III

Before DNA testing was possible (or DNA was known about) plants were collected into families, classes and orders according to detailed studies of how they looked.

Over the past few hundred years there have been many different classification systems, but one of the most commonly used and straightforward was the Cronquist System, devised in 1968. This System grouped plants into families, with the families grouped into orders, orders then grouped into sub classes and sub classes grouped into two classes: monocotyledons and dicotyledons. However, with genetic testing, it has been found that many of these groupings were wrong. A new system, called APG (Angiosperm Phylogeny Group), was introduced in 1998, but has subsequently been updated twice since then and will no doubt change in the future.

Frustratingly, what was once a very neat and straightforward system of classification has become an unwieldy, confused and messy system, because nature is never neat. The new system, called APG III, does not use classes and subclasses, instead it groups orders within clades, nested within other clades, nested within other clades; with some families not fitting into any clade at all.

The following diagrams are an attempt to show the changes in a simple manner, using images of plants to represent different orders and showing how those orders have altered their connection to others. It is clear that some assumptions were completely wrong, for example some dicots are more closely related to monocots than other dicots; the buttercup is not kindred with the water lily; cacti are more connected to Heuchera than originally thought and oak trees are closer to Euphorbia than London planes.

Cronquist system

Cronquist system

APG III System

APG III System

Key to Magnoliophyta plants

Key to Magnoliophyta plants

Note: I was unable to take photos of a tulip tree or Rhododendron in flower, so used photos I got online from here: Rhododendron and tulip tree

 

It was also fairly tricky to find all the necessary information about where plants appear in the Cronquist system, if anyone spots any faults, please contact me at the email to the right. Most of my information came from Wikipedia, and from here

To enlarge the key click the thumbnail

Anthurium and Ctenanthe - two flowering plants

Anthurium and Ctenanthe – two flowering plants