Lesson 3 RECOGNISING PLANT FAMILIES AND IDENTIFYING PLANTS Aim Distinguish between different plant families and to become proficient at identifying plants. The best way to build your ability to identify plants is by working with or handling a variety of different plants on a daily basis. The first ten plant names you learn are always much more difficult than the next ninety. Similarly, the first 100 names are always much more difficult than the next 900. If you plan to be a skilled gardener, landscape designer, or horticulturist: you need to learn to identify hundreds of different plants. As you have seen earlier; there is a system in identifying plant names. BECOME FAMILIAR WITH PLANT FAMILIES If you can get to know the way the system works, and the broad categories, the whole thing starts to make a great deal more sense. Each new name you confront is able to be associated with things and remembered more easily. FOR EXAMPLE: “When I see a plant with a daisy flower, I immediately know that it is in the Asteraceae family. Even if the genus is new to me, I will be more likely to remember it because I’m not only thinking: This is the genus of this new plant , but I am also thinking: This new genus is in the Asteraceae family. In essence, my brain is registering two pieces of information instead of one and that doubles the likelihood of me remembering the plant. BECOME FAMILIAR WITH LATIN Plant naming is based on the ancient Roman language of Latin. For most people scientific names are a foreign language when they start learning them. In the same way that it can be hard to pronounce a French or Chinese word for the language student it can be difficult to pronounce a new plant name for the horticulture student. The horticulture student has one huge advantage though. It doesn’t really matter how you pronounce plant names. The system of plant naming is all about how you write them, and experts all over the world pronounce the same names all sorts of different ways. As you become familiar with different names and more comfortable with using them, it then becomes a great deal easier to read, remember, and even pronounce new names that you come across. ONCE YOU KNOW THE PLANT FAMILY, IT’S A LOT EASIER TO FIND OUT THE GENUS YOUR FIRST AIM Your first important task should be to learn some of the most common plant families, and the things that distinguish plants as belonging to that family. When you know a plant belongs to the Asteraceae family, in an attempt to identify it, you may only need to look through photographs in 2% of a book, of plants belonging to that family. If you don’t know what family it belongs to though, you may need to look through the entire book. The first step is to determine if the plant is an Angiosperm (flowering plant) or not. Angiosperms are plants that produce flowers, and these make up most of our garden and crop plants. Plants that are not angiosperms include Ferns, Conifers, Mosses and Algae. None of these plants produce a flower. If the plant is an Angiosperm it will either be a Dicotyledon or a Monocotyledon. You can tell these two groups apart easily as follows: MONOCOTYLEDON CHARACTERISTICS DICOTYLEDON CHARACTERISTICS When a seed germinates, only one leaf When a seed germinates, two leaves emerge with the (ie. cotyledon) emerges from the seed at first. first growth. Leaf veins usually run parallel to each other Leaves normally have branching veins that fan out and are not parallel to each other (but there are exceptions) The stem doesn’t form growth rings The stem forms growth rings. (ie. if you cut through the trunk of a tree, you can tell the number of years it has lived by counting the rings) Flower parts usually occur in multiples of three Number of flower parts vary from family to family (eg. three petals) –but there are exceptions Has a fibrous root system Has a main tap root with lateral branches EXAMPLES OF MONOCOTYLEDONS EXAMPLES OF DICOTYLEDONS Daffodil, Tulip, Grasses, Hippeastrum, Sedges Eucalyptus, Maple, African Violet, Pea, Cucumber SELF ASSES SMENT Perform the self assessment test titled ‘Test 3.1’. If you answer incorrectly, review the notes and try the test again. WHAT IS THE WOOD LIKE? Another major way to distinguish plants is by the hardness or softness of the tissue. CHARACTERISTICS OF WOODY PLANTS HERBACEOUS PLANT CHARACTERISTICS Older wood in stems is hard. Older wood is soft. It would be difficult for the average person to crush even a small piece of stem (say 5mm thick) between your fingers. Stems are difficult to mark significantly with Stems are easy to mark with your finger nails your finger nails When you crush wood (not leaves), not much When a stem (not leaf) is crushed, drops of moisture moisture is squeezed out can be squeezed out. Mostly Dicotyledons Includes most monocotyledons, and some dicotyledons as well. TRY LEARNING THE FOLLOWING FLOWERING PLANT FAMILIES TO START WITH: Some plant families are more common than others. Some families are also very easy to recognise. Try learning the characteristics of the following common plant families: AMARYLLIDACEAE • Monocotyledons • Contains more than 65 genera • Most are herbaceous • Most are small clump forming herbs or bulbs • Leaves are usually narrow, often strap like • Flowers have what looks like 6 petals surrounding a cup or tube like crown (in fact these are three petals and three sepals). The cup is more obvious in some genera than others. • Flowers have 6 stamens • Genera in this family include: Alstroemeria, Amaryllis, Clivia, Cooperia, Crinum, Cyrtanthus, Eucharis, Galanthus, Haemanthus, Hymenocallis, Hypoxis, Lycoris, Narcissus, Nerine, Sprekelia, Vallota and Zephranthes. These strappy leaves are common in the Amaryllidaceae family Typical flowers of the Amaryllidaceae family ARACEAE • Commonly called “Aroids” • Dicotyledons • Most are herbaceous • Contains around 115 genera • Leaves are usually roughly heart shaped • Fruit is a berry • Flowers are small and clustered into a spike (often a finger like protrusion), with a single often colourful leafy like structure. These are commonly called “spathe” flowers. • Genera include Acorus, Anthurium, Calla, Caladium, Calocasia, Diffenbachia, Philodendron, Syngonium, Zantedeschia A typical Araceae leaf A typical flower of the Araceae family, showing the distinctive spike and surrounding spadix ASTERACEAE (formerly called Compositae) • Commonly known as Daisies • Dicotyledons • Many are herbaceous, but not all. • A very large family of about 800 genera and 12,000 species. • Flowers are actually a composite of several small flowers fused together to appear as one flower. • If the flower is pulled apart it can be seen that it is made up of several individual units, each one having its own set of floral parts (ie. petal, stamen, stigma, ovary etc). Some Asteraceae flowers are incomplete and have only some of the floral parts. Typically, the outer flowers have “ray florets”, which look like the petals of the “larger” composite flower. • Leaf shapes vary a lot. • Many have a white milk sap –but there are many exceptions • Genera include Achillea, Aster, Bellis, Chrysanthemum, Cinneraria, Centaurea, Coreopsis, Dahlia, Erigeron, Helianthus (Sunflower), Helichrysum, Lettuce(Lactuca), Tagates (Marigold), Pyrethrum, Rhodanthe, Rudbeckia, Senecio, Tansy (Tanacetum), and Zinnia Typical “flowers” from the Asteraceae family – really these flower heads are each one, made up of a lot of individual flowers joined together to create what looks like a single flower. ERICACEAE (Heath Family) • Commonly called the Heath Family • Dicotyledons • Around 70 genera and 2000 species, but tens of thousands of named cultivars. • Most are shrubs or small trees, with woody stems. • Occur mostly in cooler places (eg. temperate climates or mountain regions in the tropics) • Grow naturally and best on organic acid soil. • Leaves are frequently evergreen, and often more or less leathery (but there are plenty of exceptions) • Leaves normally alternate up the stem (sometimes whorled, rarely opposite) • Flowers have 4 to 5 sepals and 4 to 5 petals arranged evenly, often tube like. • The fruit is frequently a capsule, but sometimes a berry. • Genera include Andromeda, Arbutus, Calluna, Daboecia, Erica, Kalmia, Pieris, Rhododendron (which includes Azalea), and Vaccinium (ie. Blueberry) Erica Rhododendron LAMIACEAE (= Labiatae) • Commonly called the Mint family. • Dicotyledons • Many are herbaceous • Includes around 160 genera and 3000 species. • Stems are roughly four sided (i.e. similar to a square or rectangle in cross section). • Leaves are simple (ie. not divided like a pinnate leaf), and are whorled. • Flowers are two lipped (ie. Half of the petals are larger and fused to make the top section and the other half smaller, joined together to make a lower section. • Often the foliage is covered with small dots containing a volatile oil. This allows identification by smell when leaves are crushed • Genera include: Coleus, Lavendula (Lavender), Mentha (Mints), Origanum (Oregano and Marjoram), Plectranthus, Prostranthera, Rosmarinus (Rosemary), Salvia (Sage)Thymus (Thyme), Westringia. Typical Lamiaceae plants FABACEAE (= Papilionaceae) • Commonly called the Pea family • A Dicotyledon • Includes both herbaceous and woody plants • The 'Peas' were reclassified in recent years, splitting the one old family Leguminosae (ie. Legumes), into three new families (ie. Caesalpinaceae, Mimosaceae and Fabaceae or Papilionaceae). Many people still use the old name though. • All legumes are characterised by a pod type fruit. • There are around 500 different genera of legumes • Fabaceae flowers are pea shaped, with 5 sepals and 5 petals. Unlike other legumes, 2 of the 5 petals are joined to form a “keel” or boat like structure. The other 3 petals are free or separate one from the other • Fabaceae genera include: Arachis (Peanut), Cytisus (Broom), Dillwynia, Glycine (Soybean), Hardenbergia, Kennedya, Medicago (Lucerne), Phaseolus (Pea and Bean), Trifolium (Clover), Wisteria.