Chapter 3 BASIC BOTANY IDAHO MASTER GARDENER UNIVERSITY OF IDAHO EXTENSION Introduction 2 Plant Nomenclature and Classification 2 Family 3 Genus 3 Species 3 Variety and Cultivar 3 Plant Life Cycles 6 Annuals 6 Biennials 6 Perennials 6 Plant Parts and Their Functions 7 Vegetative Parts: Leaves, Stems, and Roots 7 Reproductive Parts: Flowers, Fruits, and Seeds 10 Plant Development 14 Seed Germination 14 Vegetative Growth Stage 14 Reproductive Growth Stage 14 Senescence 15 Further Reading and Resources 15 CHAPTER 3 BASIC BOTANY 3 - 1 Chapter 3 Basic Botany Jennifer Jensen, Extension Educator, Boundary County Susan Bell, Extension Educator, Ada County William Bohl, Extension Educator, Bingham County Stephen Love, Consumer Horticulture Specialist, Aberdeen Research and Extension Center Illustrations by Jennifer Jensen INTRODUCTION varying from country to country, region to region, and sometimes even within a local area. This makes Botany is the study of plants. To become a it difficult to communicate about a plant. For knowledgeable plant person, it is essential to example, the state flower of Idaho is Philadelphus understand basic plant science. It is important to lewisii , commonly called syringa in Idaho. In other understand how plants grow, how their various parts parts of the country, however, the same plant is function, how they are identified and named, and known as mock orange. To add to the confusion, how they interact with their environment. Learning Syringa is the genus for lilac shrubs. Another the language of botany means learning many new example of confusing common names is Malva words. Making the effort to learn this material will parviflora , which is called little mallow, round leaf prove extremely valuable and will create excitement mallow, cheeseweed, or sometimes buttonweed. The as you learn to unravel the mysteries of the plant same common name may also be used for several world. plants. An example is the common name geranium, Like all living organisms, plants are complex, and which can refer to plants in either the genus there is far more to know about them than can be Geranium or the genus Pelargonium . learned in an introductory Master Gardener course. With scientific names, a plant has only one name. Nonetheless, this chapter is designed to provide the Scientific names use the Latin language and often Master Gardener student with a brief, but broad, are descriptive of some characteristic of the plant. A introduction to many aspects of botany. dictionary on plant names can help with pronunciation and clarify the meaning of Latin PLANT NOMENCLATURE AND words. CLASSIFICATION Plants are named using a binomial (two-part) Plant classification and the scientific naming of naming system. A binomial name includes the plants are important for correct and precise plant’s genus name (capitalized and italicized) plus identification. Plant classification can be useful for the specific epithet name (lowercased and Master Gardeners involved in identifying plants, italicized). The name may be followed by the initial germinating seeds, growing a garden, diagnosing of the person credited with originally describing and plant problems, or controlling pests. naming the plant. For example, Solanum L. indicates that Carl von Linne Plants generally have a common name and a tuberosum (Linnaeus), a Swedish physician, described and scientific name. Common names are usually simple named the white (Irish) potato. and easy to remember for the general public. They often are descriptive of the plant; for example, Plant classification groups plants with similar burning bush, bleeding heart, or paper birch. characteristics, first in a broad sense, then through a series of subgroups, using progressively more There are problems, however, with using specific flower and plant traits. This process common names. The same species of plant may continues until a single, unique plant form remains. have two or more common names, with names 3 - 2 BASIC BOTANY CHAPTER 3 This plant is given a binomial species name. Ranked In a family of plants, similarities occur primarily from general to specific, the plant classification with reproductive parts (flowers, fruit, and seed), groups are as follows: kingdom, division or phylum, although leaves and other plant parts may also be class, order, family, genus, species, and variety or similar. Table 2 includes some common families and cultivar. Each species is assigned to a genus, each some of their characteristics. genus to a family, and so on. Refer to Table 1 for Genus examples of plant classification. Genus is a subdivision of a plant family. Plants of Understanding plant classification is useful for the same genus share similarities mostly in flower maintaining a successful garden. For example, characteristics and genetics. Plants in one genus vegetable crops should be rotated each year, and usually cannot breed with plants in another, but rotation can be simplified by grouping plants from species within a genus will often intercross. The the same family. To do so, you need to know which first letter of the genus name is capitalized, and the plants belong in which family. A second example: entire name is italicized or underlined. when using the Internet to research solutions to a plant problem, it is absolutely essential to enter the Species correct scientific name. The more you study plants, Species is a group of individual plants that freely the more you likely will appreciate the usefulness of interbreed and have many (or all) characteristics in the scientific nomenclature system. common. Species names use the binomial naming system of genus and specific epithet. An important distinction among plants at the Division level is between those with seedlings Variety and cultivar having one seed leaf ( monocots , such as grasses Variety and lilies) and those with seedlings having two seed Variety is a word commonly used to describe leaves ( dicots , such as beans). Monocot and dicot cultivated and hybridized plant types. This is a seeds germinate differently. The distinction between misnomer; used in its proper context, a variety is a monocots and dicots becomes very important when botanical division of a species. It is a subgrouping using herbicides. For example, common lawn of plants within a species that differs in some herbicides for broadleaf weeds (for example, 2,4-D) particular way from other members of that species. will kill only dicot plants, leaving the grass plants In the wild, variety may be used to describe a (monocots) unharmed. particular regional variant of a species with unique Family plant size, flower color, or other visible trait. In Master Gardeners usually work with the cultivated plants, variety may be used to designate a classification of plants at the family level and below. particular useful form of a species. For example, Plant families are important in gardening because cauliflower ( Brassica oleracea var. botrytis ) and members of the same family often have similar cabbage ( Brassica oleracea var. capitata ) are cultural requirements and similar insect and varieties of the same species. The variety name disease problems. follows the abbreviation “var.” It is written in lower case and is italicized or underlined. Table 1. Examples of plant classification. Common name Black chokecherry Siskiyou blue Idaho fescue Western white pine Kingdom Planta Planta Planta Division or phylum Magnoliophyta Magnoliophyta Pinophyta Subdivision Angiospermae Angiospermae Gymnospermae Class Magnoliopsida (dicots) Liliopsida (monocots) Pinopsida Order Rosales Poales Pinales Family Rosaceae Poaceae Pinaceae Genus Prunus Festuca Pinus Species Prunus virginiana Festuca idahoensis Pinus monticola Variety or cultivar var. melanocarpa ‘Siskiyou Blue’ CHAPTER 3 BASIC BOTANY 3 - 3 Table 2. Common plant families. Scientific Common family name family name Common plants in family Family traits Apiaceae Carrot family Carrot ( Daucus carota ) Flowers usually in simple or Parsnip ( Pastinaca sativa ) compound, flat-topped clusters Dill ( Anethum graveolens ) called umbels; stems often Poison hemlock ( Conium maculatum ) hollow. Asteraceae or Sunflower family Lettuce ( Lactuca sativa ) Flowers organized as heads Compositae Sunflower ( Helianthus annuus ) with ray and disk flowers. One Zinnia ( Zinnia elegans ) of the largest families: 20,000 Spotted knapweed ( Centaurea stoebe ) species. Brassicaceae or Mustard family Broccoli ( Brassica oleracea var. botrytis ) Flowers have four petals that Cruciferae Kale ( Brassica oleracea var. acephala ) are not joined; there usually are Cabbage ( Brassica oleracea var. capitata ) six stamens (four long, two Radish ( Raphanus sativus ) short). Shepherd’s-purse ( Capsella bursa-pastoris ) Fabaceae or Pea or bean family Common pea ( Pisum sativum ) Flowers with a distinct upper Leguminosae Common bean ( Phaseolus vulgaris ) “flag” petal, arranged in heads Lupine ( Lupinus argenteus ) or spikes. Hairy vetch ( Vicia villosa ) Lamiaceae or Mint family Peppermint ( Mentha x piperita ) Leaves usually opposite; flowers Labiatae Sweet basil ( Ocimum basilicum ) tubular; stems square. English lavender ( Lavendula angustifolia ) Henbit ( Lamium amplexicaule ) Poaceae Grass family Corn ( Zea mays ) Leaves simple and strap-like; Kentucky bluegrass ( Poa pratensis ) inflorescence usually a long Blue fescue ( Festuca glauca ) spike. Large family of between Quackgrass ( Elytrigia repens ) 7,500 and 10,000 species. Ranunculaceae Buttercup family Columbine ( Aquilegia vulgaris ) Large and