Understanding the Flowering Plants E-Book

Anne Bebbington

• Herausgeber: Crowood
• Kategorie: Geisteswissenschaft
• Sprache: Englisch

Seitenzahl: 325

Veröffentlichungsjahr: 2014

Beschreibung

To study a plant in detail is to make a fascinating journey of discovery. Even plants we think we know well will often surprise us as we look at the intricacy of their structure and how they are put together. This fascinating guide explains what flowering plants are and their relationship to other groups of plants. With drawings, paintings and photographs throughout, it advises on how to carry out a botanical study and will prove essential reading for botanical artists, photographers and all those wishing to gain a greater understanding of flowering plants. Contents include: practical advice on techniques, tools and other equipment used in botanical work; the structure and function of the main parts of the flowering plant, highlighting features that are important in illustration for botanical purposes; suggestions for projects, which can be used to assess your understanding or stimulate the start of a new project. Superbly illustrated with 366 colour images.

Leseprobe

Understanding the Flowering Plants

A practical guide for botanical illustrators

Anne L. D. Bebbington

THE CROWOOD PRESS

First published in 2014 by

The Crowood Press Ltd

Ramsbury, Marlborough

Wiltshire SN8 2HR

www.crowood.com

This e-book published in 2015

© Anne Bebbington 2014

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers.

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

ISBN 978 1 84797 759 5

Frontispiece: A worker Early Bumblebee nectaring on the flower of a Dusky Cranes-bill (Geranium phaeum)

Dedication

For Mary Brewin, my co-tutor in running the first ‘Botany for Botanical Artists’ course in 2010. Without her, this course would not have happened, nor been such a success.

Acknowledgements

I am deeply indebted to my husband John, not only for taking the majority of photographs in this book, but also for his tremendous help in checking all the material and for his support and encouragement. I am very grateful to Mary Brewin, Jan Cheshire, Catherine Day, Ros Franklin and Ken Victor for permission to use their artwork, and to Melvin Grey, Robert Sharrad, David and Madeleine Spears and Ruth Thomas for use of their photographs. I thank Science and Plants for Schools (SAPS) for permission to include the simple idea for measuring tree height.

All photographs except those accredited otherwise are by John Bebbington FRPS.

All artwork except that accredited otherwise is by the author.

CONTENTS

Introduction

Preface

1.

WHAT IS A FLOWERING PLANT?EVOLUTION; MAJOR GROUPS IN THE PLANT KINGDOM; THE FLOWERING PLANTS AND THEIR CLASSIFICATION; MAJOR GROUPS WITHIN THE FLOWERING PLANTS; PLANT NAMES; WRITING PLANT NAMES

2.

THE APPROACH TO A BOTANICAL STUDYDECISIONS TO MAKE BEFORE YOU START; RESEARCHING YOUR SUBJECT; CHOOSING AND COLLECTING MATERIAL; LOOKING AFTER YOUR PLANT MATERIAL; BOTANICAL ILLUSTRATION AND ARTISTIC LICENCE; KEEPING A RECORD

3.

TOOLS AND TECHNIQUESTOOLS; PRACTICAL TIPS AND TECHNIQUES; INDICATING SIZE; PHOTOGRAPHY AND BOTANICAL ART; COMPUTERS AND SCANNERS

4.

THE FLOWERING PLANT – STRUCTURE AND LIVING PROCESSESTHE PARTS OF A PLANT; PHOTOSYNTHESIS; RESPIRATION; MINERAL NUTRITION; PARASITES AND SAPROPHYTES; TRANSPORT; TRANSPIRATION AND THE CONTROL OF WATER LOSS; GROWTH; PLANT BEHAVIOUR

5.

LEAVESTHE BASIC STRUCTURE OF THE LEAF; SIMPLE AND COMPOUND LEAVES; LEAF ATTACHMENT; LEAF ARRANGEMENT; CHOOSING LEAVES TO ILLUSTRATE; LEAVES WITH SPECIAL ADAPTATIONS; INSECTIVOROUS PLANTS

6.

ROOTS AND STEMSMAIN FUNCTIONS; DISTINGUISHING ROOTS FROM STEMS; EXTERNAL FEATURES OF ROOTS AND ROOT SYSTEMS; ADVENTITIOUS ROOTS; EXTERNAL FEATURES TO OBSERVE ON STEMS; SPECIALIZED ROOTS AND STEMS; LIVING IN VERY DRY PLACES – CACTI, SUCCULENTS AND OTHERS

7.

LIFE SPANS AND ASEXUAL REPRODUCTIONLIFE SPANS; SURVIVING AND REPRODUCING; VEGETATIVE REPRODUCTION; ORGANS OF VEGETATIVE REPRODUCTION; GARDENING AND THE REPRODUCTION OF PLANTS

8.

FLOWERSEXAMINING A FLOWER; THE BASIC STRUCTURE OF A FLOWER; SEPARATE MALE AND FEMALE FLOWERS; FLORAL FORMULAE, DIAGRAMS AND HALF FLOWERS; THE INFLORESCENCE

9.

SEXUAL REPRODUCTIONTHE GENETICS, AN INTRODUCTION; CROSS-POLLINATION AND SELF-POLLINATION; THE TRANSFER OF POLLEN; STUDYING POLLINATION MECHANISMS; INSECT POLLINATION – SOME EXAMPLES

10.

FRUITS AND SEEDS AND THEIR DISPERSALDESCRIBING FRUITS; THE FRUIT – ITS DEVELOPMENT AND STRUCTURE; THE MAIN FRUIT TYPES; FALSE FRUITS OR PSEUDOCARPS; DISTINGUISHING FRUITS FROM SEEDS; SOME POPULAR SUBJECTS FOR ILLUSTRATION; FRUIT AND SEED DISPERSAL

11.

SEEDS – THEIR STRUCTURE AND GERMINATIONTHE STRUCTURE OF SEEDS; DORMANCY; GERMINATION; IDENTIFYING SEEDLINGS

12.

WINTER TWIGSWHAT IS A TREE? TREES IN WINTER; TWIG FEATURES; BUD STRUCTURE; PRICKLES, SPINES AND THORNS; DIAGNOSTIC FEATURES; WINTER TWIGS WITH FLOWERS

Appendix I: The self-assessment projects

Appendix II: Template for floral diagrams

Appendix III: Glossary

Appendix IV: Bibliography

Appendix V: Equipment suppliers

Appendix VI: Societies and courses

Index

INTRODUCTION

Botanical art lies along a spectrum linking art and science. As a botanist, my illustrations are most often done for scientific purposes but I greatly value and appreciate the knowledge and skills of those whose work has its origins in the world of art.

Part of my botanical training was a regular requirement to produce drawings and diagrams. ‘If you can draw it, you understand it’ was the maxim. This stimulated and guided my investigations and has given me a lifelong fascination with the intricacies of how plants are put together and how they work. It also gave me a real appreciation of the value of illustration to a botanist.

In 2004 Michael Hickey, an accomplished artist as well as a very knowledgeable botanist, founded the Institute for Analytical Plant Illustration (IAPI), an excellent forum for botanists and artists to meet and learn from each other. It was through IAPI that Mary Brewin and I came together to run a series of practical workshops. Our aim was to help botanical artists to gain a better understanding of the flowering plants and so inform their artwork, and also to share ideas about illustration techniques appropriate to different botanical subjects. An important part of the learning process was the completion of a self-assessment project between the workshops, designed not only to help students to assess their understanding but to encourage them to ask questions and research their subjects.

This book is based on material from the course, concentrating on the structure of the flowering plants and the role that different parts play in the plant’s success and survival in its natural environment. I hope not only that those who illustrate plants will find this book useful, but also that it will help to make botanical art in general more interesting and enjoyable.

PREFACE

About the book

Although written particularly with botanical artists in mind, this book should also help anyone wishing to gain a greater understanding of the flowering plants. It starts with advice on how to approach a botanical study and introduces useful practical techniques, tools and equipment. This is followed by an explanation of the terms used to describe the main parts of a flowering plant and its living processes. Succeeding chapters take each part of the plant in turn and describe their basic structure and the role they play in the life of the plant. Features of particular importance, which should be carefully observed, are highlighted. Suggestions for projects are made at the end of each of these chapters. These can be used if you wish to help assess your understanding of the chapter’s contents or can be used to stimulate ideas for a new project. Appendix I gives advice on carrying out these projects, together with two completed examples.

For those who are just looking for information about a specific part of the plant the contents page gives an outline of the topics covered in each chapter, allowing you to dip in and out of the book.

Insect visitors are not only important for pollination. This black ant feeding on an extra-floral nectary of Common Vetch (Vicia sativa) helps protect the plant from other small animals that might eat it.

CHAPTER 1

WHAT IS A FLOWERING PLANT?

EVOLUTION

Over millions of years, evolutionary developments along numerous branching pathways have given rise to huge numbers of different living organisms. When there are large numbers of items (such as living organisms), our senses become overwhelmed with information. Sorting things into groups helps us to see patterns reflecting differences and possible relationships.

Fig. 1.1 A flowering plant – the Rock Speedwell (Veronica fruticans).

Fig. 1.2 How evolution works.

MAJOR GROUPS IN THE PLANT KINGDOM

In the Plant Kingdom the major groups recognized today are the mosses and liverworts (Bryophytes), the ferns and their allies (Pteridophytes) and the seed plants (Gymnosperms and Angiosperms). The algae and fungi (and therefore the lichens), once part of every botanist’s education, are now considered to be sufficiently different to be assigned to separate kingdoms!

Fig 1.3 The major groups of plants.

It is thought that these major groups of plants all evolved from a common, marine algal ancestor. In the move from the sea to life on land some major reproductive hurdles had to be overcome. How could the swimming male sperm reach the female egg without water, and how could the female egg be protected from drying out? The more primitive land plants, the mosses and liverworts, together with the ferns and their allies, have only partly solved this problem. The egg cells and the embryo which develops from the fertilized egg are at least initially protected by the maternal tissue. The sperm, however, is still reliant on a film of water in order to swim to the female organ and so, in order to enable sexual reproduction to take place, these plants are restricted to habitats that are damp, at least from time to time. In the seed plants protection has gone a stage further. The egg cell, and after fertilization the embryo, are enclosed and protected inside the seed. In most seeds there is also a store of food, giving the embryo a start in life. The male sperm no longer have to swim to the female but are contained within pollen grains. With their tough outer coat, pollen grains can travel long distances through the air, carried by wind or animals, to reach the female organs, only releasing the sperm in the proximity of the female egg cell. Thus for sexual reproduction these plants are now liberated from the need for damp conditions.

THE FLOWERING PLANTS AND THEIR CLASSIFICATION

The flowering plants (Angiosperms), the most evolutionarily developed of the seed plants, appeared about 135 million years ago and now dominate our planet. Not only is the developing embryo protected by the seed, but the seed itself has become enclosed by an ovary, which, as the embryo begins to develop, forms the fruit. The other major group of seed plants, the conifers and their allies (Gymnosperms), has taken another route; here the seeds are not completely enclosed by an ovary, although in the conifers woody scales forming a cone help to protect the seeds.

Since the era of the ancient Greeks there have been many attempts to classify the flowering plants, with one of the best-known being that by Linnaeus, an eighteenth-century naturalist. Sexual reproduction in plants and animals was a subject of much interest in the seventeenth and eighteenth centuries, and it was on the arrangement of the male and female sexual organs of the plants that Linnaeus based his classification system. In the descriptions, however, he drew extraordinary comparisons with human love. For example, in an essay written in 1730 he describes the function of the petal: ‘in itself it contributes nothing to generation but serves as the bridal bed, which the Great Creator arranged so beautifully, and garnished with such precious bed-curtains, and perfumed with so many scents, in order that the bridegroom and his bride may therein celebrate their nuptials with so much greater solemnity’ (Silvertown, 2009). Descriptions such as this drew the wrath of the Church down upon his head. In spite of this, the characteristics of the flower have proved to show less variability than other parts of the plant and remain an important part of modern classification systems today.

a) Wellingtonia cones (Sequoiadendron giganteum) showing the woody scales which help to protect the naked seeds. The word Gymnosperm comes from the Greek Gymnos meaning naked. It is the same root as the word gymnast comes from, the early Greek athletes normally exercising and training without any clothes on!

b) Developing fruit of Red Campion (Silene dioica) showing seeds completely enclosed within the ovary. Angiosperm derives from the Greek word angeion meaning a vessel or container.

Fig. 1.4 Cones of a Gymnosperm compared with the fruit of an Angiosperm.

Until recently, classification systems were largely based on visual observations, but with modern advances in the study of genetics, we now have a much better understanding of the real relationships between living organisms and their evolutionary pathways. Although on the downside this means that some groupings and names with which we have become very familiar over time have changed, a classification system based on this new information is likely to be much more robust and stand the test of time.

a) Great Yellow Gentian (Gentiana lutea) a dicot, with 5–9 perianth parts and leaves with parallel veins.

b) Black Bryony (Tamus communis) a monocot, with flower parts in multiples of three but broad leaves which look as though they have net veining.

Fig. 1.5 Examples of a dicot and a monocot whose appearance may be confusing.

MAJOR GROUPS WITHIN THE FLOWERING PLANTS

Two major groups have long been recognized: the monocots (Monocotyledons) with one seed leaf, and the dicots (Dicotyledons) with two seed leaves. It is not always easy to see this diagnostic feature, especially in the smaller seeds (see Chapter 11). There are, however, other characteristics that can help you to distinguish these two groups, but watch out – not all plants show the characteristics typical of their group!

Fig. 1.6 Differences to look for when distinguishing dicots from monocots. Differences in the internal anatomy also occur but are not included here.

Fig. 1.7 Examples of plants included in the major groups of flowering plants.

DNA data suggest that there are several primitive families which were formerly placed with the dicots but never really fitted comfortably, for example the Water Lilies (Nymphaeaceae) and Birthworts (Aristolochiaceae). It appears that these split off before the dicots and monocots separated. These will now be called predicots and will be placed before the dicots, which will be known as eudicots to distinguish them.

The arrangement of major groups and families in a flora

Plants are typically arranged in floras in a sequence that reflects their evolutionary relationships. These sequences are now also subject to debate and change. The decisions are not always easy; for example, in many floras the dicots were thought to be more primitive and typically preceded the monocots. It now seems that these two groups branched off at approximately the same time from the predicots. This is obviously not easy to represent in a linear sequence and therefore in the New Flora of the British Isles (Stace, 2010) it has been decided that, after the predicots, the eudicots will continue to be placed before the monocots as this is an arrangement familiar to most British botanists. Be aware, though, that in most British floras changes have been made to the sequence of flowering plant families within these groups.

How does all this affect the botanical artist?

The most important thing to remember is that classification is man-made and is therefore always likely to change with time as research reveals new information and opinions change. This will also often result in changes to plant names. Don’t let this worry you. It is not critical if you have not been able to find the most recent name, or the plant’s name subsequently changes. The most important thing to know is that the scientific names of plants are followed by the naming authority. This enables those who need to to track down the history of the name and any changes.

PLANT NAMES

Local or vernacular names

For generations plants have been given common names, which vary from region to region. The most commonly used name for Primula veris is Cowslip in England but Coucou (Cuckoo) in French. Here in Britain Cuckoo Flower is just one of the names used for Cardamine pratensis, also commonly known as Lady’s Smock!

Even within a region where the same language is spoken you may find differences. The name ‘bluebell’, for example, is used for different plants in England and Scotland. While the history and folklore behind these vernacular names is often fascinating, it is easy to see how they can create confusion and it is important therefore to add the scientific name to your work as well as the vernacular name.

Scientific names

Educated men wrote in Latin and therefore it was the natural language to use for naming living organisms. Surprisingly, however, until the eighteenth century there was no widely accepted system for naming.

Before Linnaeus, living organisms often had as many as seven or eight Latin words in their name. Linnaeus, with his highly organized mind, not only attempted to devise classification systems for living organisms but also devised a naming system. While his classification systems have been much modified as our worldwide knowledge has expanded, particularly in the last decade in the light of modern genetic research, his binomial system of naming living organisms still forms the basis of our naming system today. In this system names of plants (and other living organisms) are reduced to two words. The first name represents the genus and the second name the species. The renaming of the potato by Linnaeus shows how much simpler these names are.

Fig. 1.8 Primula veris. This plant’s most familiar English name, the Cowslip, probably derives from the Old English cũslyppe (cowslop), as it was commonly found in meadows amongst cow dung. It has many other names of folk origin, including Buckles, Crewel, Fairy Cups, Key of Heaven, Petty Mullein, Palsywort, Peggle and Plumrocks.

a) Campanula rotundifolia, the Scottish Bluebell, commonly called Harebell in England.

b) Hyacinthoides non-scripta, the English Bluebell.

Fig 1.9 The Scottish and English Bluebells.

Naming new plants – type specimens

When a new plant is named, a type specimen – an actual example showing the defining features of that plant – must be placed in a recognized institute. The Kew herbarium, for example, contains over 350,000 type specimens. If you search the internet for Linnaean Herbarium Online, you can see examples of Linnaeus’ original herbarium sheets.

WRITING PLANT NAMES

The hierarchy of classification

It is helpful to have some understanding of the hierarchy of classification when looking for and writing plant names.

1.

Kingdom; 2. Division; 3. Class; 4. Order: Although important, these are not often quoted. It is the divisions below this level that are most commonly referred to.

5.

Family: A group of similar genera. Family names normally have the ending –aceae.

6.

Genus: A group of related species. The generic name forms the first part of the binomial name.

a) Solanum caule inermi herbaceo, foliis pinnatis integerrimis, the early Latin name for the potato plant before Linnaeus introduced the binomial system.

b) Solanum tuberosum

The much simpler name devised by Linnaeus using his binomial system

Fig 1.10 The scientific naming of the Potato.

7.

Species (abbreviated to sp. or spp. for more than one): A group of individuals closely related and interbreeding. The species name forms the second part of the binomial name. Crosses between species are not uncommon and their offspring are referred to as hybrids. Genera are more dissimilar genetically, and therefore hybrids formed from crosses between them are rare.

Other lower order sub-divisions include:

8.

Subspecies (ssp.): a sub-division of a species, for example geographically or ecologically distinct groups.

9.

Varieties (var.): groups of distinct individuals within a species that may occur in natural populations in the wild but whose status is uncertain.

10.

Cultivars are varieties with distinct features, selected and maintained by cultivation. They are not usually found in natural populations.

Rules when writing plant names

GENERAL RULES

The first part of the name, the genus, always starts with a capital letter and the second part, the species name, should be all lower case. Both names should be highlighted, for example when writing by underlining and in print by using italics. After the first mention of a genus name, it is acceptable to use only the initial letter for the genus.

The naming authority should always be included. This enables a botanist to check the history and status of the name. The authority may be indicated by the full name, by an abbreviation or just an initial. ‘L.’, for example, tells us that the plant was named by Linnaeus. The authority name should not be highlighted, and abbreviations and initials should be followed by a full stop.

EXAMPLES DEMONSTRATING COMMON RULES AND CONVENTIONS

The following examples are based on the Primula species. For simplicity, the naming authority is only given in the first example.

Fig. 1.11 Primula vulgaris Huds. (P. acaulis (L.) Hill).

Fig. 1.13 A cultivated Polyanthus plant probably originating from the hybrid P × polyantha.

Fig 1.14 Primula vulgaris ‘Apple Blossom’, a cultivar of the Primrose.

Trade designations (selling names)

Watch out for these. Sometimes the correct cultivar name is not considered attractive, so one or more extra names are chosen for marketing purposes. These are known as trade designations and their use is often associated with plants that have received legal protection under Plant Breeders’ Rights. However, the correct cultivar name must always be included on the plant label. For example: a plant in a garden centre labelled Lavender ‘Purple Ribbon’ should also have the following information: Lavandula stoechas L. ssp.pedunculata (Mill.) Rozeira ‘Purple Ribbon’.

Fig. 1.15 Primula ‘Wanda’, a variety of Primrose, the origin of which is uncertain.

INTERGENERIC HYBRIDS

Hybrids formed by crosses between genera are rare and are given new names derived from the generic names of the parents. For example, × Fatshedera lizei, the Tree-ivy, was created by crossing Moser’s Japanese Fatsia (Fatsia japonica ‘Moserii’) with the Ivy (Hedera helix).

When adding a plant name to your work the best advice is that you should use the most up-to-date flora or horticultural work available to you to check the name. In the UK the web sites of organizations such as the Botanical Society of the British Isles, the Royal Horticultural Society and the Royal Botanic Gardens, Kew can also provide useful sources of information.

CHAPTER 2

THE APPROACH TO A BOTANICAL STUDY

It is assumed here that at least some degree of botanical accuracy is required in your work. However, even if you are only working to produce a pleasing picture, the advice given here will be helpful and will almost certainly make your project more interesting.

Fig. 2.1 A completed botanical study of the Common Ivy (Hedera helix L.) (Watercolour and pencil).

DECISIONS TO MAKE BEFORE YOU START

It is important to decide on the purpose of your artwork as this will determine not only your medium and other techniques, but a number of other decisions which are best made before you start.

The size of your work

Work submitted for exhibition or diplomas may have particular size requirements, but this is also true for scientific illustrations. If you receive a commission it is essential that you find out whether the illustration is to be published and what size the final image will be. In pen and ink work, for example, over-enlargement will result in any minor line wobbles or errors becoming horribly visible. It can also be very disappointing when a painting is printed very small and detail you have spent hours adding is lost! In one publication a painting of a yew branch that filled an A4 frame was reduced to an image only 2cm × 3cm!

A useful rule of thumb for artwork which you know is going to be printed is to make it one and a half times larger than the final printed version.

Composition

Obviously this is very important in exhibition work but nor should it be neglected in work for scientific purposes. For publications, the final decisions about layout and composition may not be entirely yours. However, you should always be ready to discuss this with the designers and ask to see pages at the proof stage to check that related images are placed together and that orientation and labelling are correct. It may be possible to let the designer see your preferred layout at the design stage.

The degree of botanical accuracy

This will obvious depend on whether your work is purely for aesthetic pleasure or has a requirement to be scientifically accurate. Work submitted to a botanical art society for a diploma or for an exhibition is usually required to be botanically accurate as well as pictorially pleasing. For scientific work not only is accuracy important but you will almost certainly be required to show or emphasize particular features. You should discuss this with whoever is commissioning the work before you start.

Fig. 2.2 a) Pea shoot printed at chosen size (0.75 × size of original drawing); b) Part of drawing printed larger than original, making drawing inaccuracies (examples ringed) very obvious.

RESEARCHING YOUR SUBJECT

Your work in producing a piece of art will be much more interesting if you know something about your plant’s origin and natural geographical distribution. Remember that many garden plants grow wild in other parts of the world or are bred from naturally occurring wild plants. Try to find out something about the natural environment in which the plant grows. This may explain some of the features it shows; for example, plants growing in dry habitats may have succulent water-storing leaves or stems. Knowing something about its pollination mechanism may help you to interpret the flower structure.

It is also important to be aware of the diagnostic features – the features that differentiate one type of plant from another and are used in identification. In work intended, for example, for a botanical art exhibition, provided the features shown are accurate, then not all the diagnostic features may need to be shown. These should, however, always be included in a scientific illustration, where they are often the main focus. In addition to the characteristics of the flowers, diagnostic features may include the general habit and features of roots, stems, leaves, fruits and seeds. Consult a flora (for example, Stace, 2010) to find out what the diagnostic features are. As well as books, the internet is a good source of other information. Type your plant’s name into a search engine and research the information described above. This does of course depend on having the correct name for your plant. Floras are designed for identification and you may find them, and in particular the illustrated floras, helpful. However, they can be difficult to understand (even to many botanists!). Some botanical organizations may also be happy to help you with information or will put you in touch with a botanist who can help. In the UK, for example, the Institute for Analytical Plant Illustration (IAPI) provides this service. The Botanical Society of Britain and Ireland may be able to put you in touch with a botanist who can help you with British wild flowers, whilst local Wildlife Trusts and botany groups may also be able to help. For cultivated plants you may need to approach a botanic garden or horticultural society.

Fig. 2.3 Robin’s Pincushion is an attractive but abnormal growth. This brightly coloured gall is caused by a tiny wasp that usually lays its eggs in wild roses. When the larvae hatch, the plant is chemically induced to produce the characteristic, much distorted mass of hairy growth. The larvae live inside this, feeding on abnormal cells rich in oils and protein.

CHOOSING AND COLLECTING MATERIAL

It may be that an atypical specimen, perhaps one with a virus or fungal infection (these often show interesting colour patterns) or insect damage (Robin’s Pincushion), has inspired you. Here your choice will be mainly centred on choosing a specimen that will make a pleasing composition and final piece of artwork. Try to find out what has caused the aberration, as this will give added interest to your completed piece of work.

If, however, you are trying to demonstrate the characteristic features of a particular type of plant, for example a species or cultivar, you will need to choose your specimen with care, making sure it is typical. Avoid, for example, specimens growing in unusual environmental conditions, such as deep shade. Take care when choosing horticultural specimens. A bunch of tulips bought from a local supermarket for study at a workshop had petals (tepals) ranging in number from four to seven, instead of the usual six.

Fig. 2.4 A supermarket tulip showing an abnormal number of petals (tepals).

Fig. 2.5 This image of a Shrew Mole, which looks very dead, is from a Victorian natural history book. Early illustrators often did not have access to live specimens.

Even in natural habitats there are always oddities – you should always expect to find variation, as plants don’t read the textbooks. Look at as wide a range of specimens as possible before making your choice and make sure your specimens are in good condition.

Drawing herbarium or dead specimens

Both plants and animals are sometimes drawn from dead specimens. Some artists are inspired by the shape, form and colour of such material, but in general for scientific work, wherever possible, healthy living specimens should be used. These not only result in a more pleasing picture but usually give more information.

Collecting plants from the wild and the law

It is a criminal offence intentionally to uproot a wild plant without the permission of the landowner. Although it is legal to pick wild plants unless they are protected, the legislation relating to the protection and collection of wild plants is complex. Bye-laws are also in operation in most national and local nature reserves. The best advice is check who the landowner is and always get their permission before picking anything. For any wild plant the amount of material collected should be kept to a minimum. Plants with roots should only be collected if it is essential, and should always be returned and replanted after you have finished with them. Many floras (for example, Streeter, 2009) will give you guidance about the rarity and vulnerability of individual species, and at-risk plants should always be left alone unless permission has been specifically granted for scientific purposes. Field sketches and photographs may be an important part of your preliminary work, but take care not to trample and damage a plant’s habitat while doing this.

LOOKING AFTER YOUR PLANT MATERIAL

Plants vary in their tolerance to picking but the following general rules will apply to most. For more information about caring for picked specimens of special groups of plants, see Oxley (2008).

1.

The best time to collect specimens is either early in the morning or in the late afternoon/early evening. At midday, especially when it is hot and sunny, many plants will be close to their wilting point and may not recover from being picked.

2.

If possible, put the stems of your specimens straight into water or, if you are transporting them some distance, place the whole specimen into an inflated polythene bag into which water has been sprinkled. Alternatively use a plastic box lined with wet tissue, covering the plant with another layer of damp tissue. Containers such as film pots are very useful for small specimens. If you are not able to begin your drawing within twenty-four hours, many plants will survive for at least a few days in these containers in an ordinary domestic refrigerator. The low temperature will also slow down growth and the opening of buds.

3.

On reaching home, fill a jar with water and use a sharp knife to cut off about 2cm of stem below the surface of the water. This removes the lower part of the stem in which airlocks may have formed and makes sure that water can reach the upper parts of your specimen. (The cut portion usually floats to the water surface and can be easily removed.) Some plants survive better if the cut stems are immediately plunged into boiling water for a few seconds before placing them in your water jar. You can also use this technique if you are cutting stems of plants which produce a lot of latex, for example the spurges (family Euphorbiaceae). Latex can be a strong irritant and you should avoid skin contact. Use protective gloves to cut the stem and seal the end of the stem with boiling water as above.

4.

Once it is in water, allow your specimen time to recover fully before beginning your work, especially if it is showing any sign of wilting.

WHAT IS LATEX?

About 10 per cent of plant species produce latex. It is commonly white but can be colourless, yellow, orange or even red. It is produced in special latex cells and is not the same as plant sap. Its functions are mainly concerned with defence against herbivores and also protecting the plant from injuries, by coagulating and sealing wounds, thus preventing the entry of bacteria and fungi.

Latex from some plants is also of economic importance. Natural rubber, for example, is a product of the rubber tree Hevea brasiliensis, a member of the spurge family, and a number of opiates come from the dried latex of the Opium Poppy Papaver somniferum. Less well known but also interesting is another member of the poppy family, Greater Celandine Chelidonium majus, sometimes called the Wart Plant. It has been known for several hundred years that its orange latex can help get rid of warts. Latex is chemically very complex, however, and can contain substances that are extremely toxic to humans or can cause serious allergic reactions. Plant latex should always be treated with great caution and never used without medical advice.

Fig. 2.6 White latex exuding from the damaged stem of a Spurge (Euphorbia sp.).

Fig. 2.7 Bright orange latex at the base of the stem in Greater Celandine (Chelidonium majus).

Dealing with damaged specimens

Occasionally, especially if you are working on a rare specimen, you may have to work on material sent to you through the post. If you know this is likely to happen, contact the collector and make sure the package is sent to you at a time when you are at home and ready to receive it. Even so, the specimen may be in pretty poor condition, but all is not lost; you can try some first aid! Remove it from its packaging as soon as you are able to, put it into a jar of water, cutting the stem under water, and allow it to recover in a cool place. However, recovery is unlikely to be complete and you will almost certainly have to use information collected from sketches and photographs of parts of the plant as it recovers. Even when recovery looks unlikely, it is worth a try.

The plant in Fig. 2.8 had arrived through the post. The stem had been folded to fit it in the box and all the flowers had dropped off. Only one bud remained. The plant did, however, have some roots. I drew the remaining bud and planted the specimen in a pot, splinting the stem to straighten it, watered it well and put it in a cool place, hoping it would recover.

Fig. 2.8 Treatment of damaged plant. The specimen has been splinted to support the damaged stem and kept in a cool place for several days.

Meanwhile I collected as much information as possible from the flowers lying in the box, using sketches and photographs. After spending several days in ‘intensive care’, the flower bud opened and amazingly the plant was sufficiently recovered for me to complete my study.

BOTANICAL ILLUSTRATION AND ARTISTIC LICENCE

Those artists who have little botanical background but who, with their great observational skills and technical abilities, are able to reproduce accurately an image of the specimen in front of them, are admirable. Certainly the general advice is that you should draw what you see, but are there times when some artistic licence should be allowed? Here are some suggestions. When it is important to show features that are particularly characteristic of the species, for example, for a botanical flora:

All plants show a greater or lesser degree of variability and a single specimen may not show all the typical characteristics. Your plant might also be exhibiting an unusual feature. You may therefore need to produce an illustration in which information has been drawn from a range of specimens.

The specimen is growing and developing or even wilting whilst you are trying to draw it:

Photographs and quick sketches should be made and used to inform your finished piece of work.

Some warnings if you are not going to draw exactly what is in front of you:

•

only do this if there is a good reason for it;

•

look at as wide a range of specimens as possible, including ones growing under different environmental conditions; and

•

research your subject carefully by consulting the literature (books, internet, and so on) but don’t copy information from other people’s illustrations. There is a history of mistakes being copied through several generations of illustrators.

Fig. 2.9 Completed drawing of damaged plant. a) whole plant b) detail of flower c) bottom of plant d) upper part of plant e) detail of young fruit.

KEEPING A RECORD

Throughout the work on your project keep a record of all your findings, including sketches and photographs, preferably in the form of a botanical sketchbook. As you draw, continually ask yourself questions; if there is something you do not understand or cannot see properly, make a note of it. You may be able to find the answers by looking at more material, or through your research into other people’s work. Your sketchbook will be an invaluable record to which you will be able to refer back as you continue your botanical work and tackle other projects.