Plant Identification PDF

HO-97 Plant Identification By Marty Wingate, Master Gardener, King County, Washington State University. Adapted for use in Kentucky by Richard Dur- ham, consumer horticulture Extension specialist and state Master Gardener coordinator, University of Kentucky....

HO-97 Plant Identification By Marty Wingate, Master Gardener, King County, Washington State University. Adapted for use in Kentucky by Richard Dur- ham, consumer horticulture Extension specialist and state Master Gardener coordinator, University of Kentucky. Plant Names In this chapter: Plants follow the same kind of classification system as do Plant Names 01 animals: kingdom, division, class, order, family, genus, and species. As gardeners, we are mostly concerned with the last Hybrids 02 three categories: Cultivars 02 Family—A broad group of plants with common character- Practicing Plant Identification 03 istics. The family name is written in plain text, its first letter is capitalized, and it ends in “aceae.” For example, the nightshade family is Solanaceae. Common plants in this family include L tomato, potato, pepper, eggplant, and tobacco. Some families earning about new plants is an exciting venture. may be listed using an older style; you may find the daisy family Sometimes you are looking for a plant to fill a certain written as either Compositae or Asteraceae, for example. That’s spot in your garden. At other times, you want to com- because sometimes taxonomists (people who make decisions plete a particular color scheme, or your attention is caught by about plant names) don’t agree. a magnificent tree, shrub, or perennial in a public or private Genus (plural genera)—A category within a family that contains garden. When you come across an unfamiliar plant, it can be related species. Families may contain a few genera or many. For frustrating to try to figure out what it is without knowing some example, the monkey puzzle tree, Araucaria araucana, is one of the botanical principles of plant identification. of only two genera in the family Auricaceae. The rose family The rules of plant identification and nomenclature (naming) (Rosaceae), on the other hand, includes more than 100 genera— may seem complex and more trouble than they are worth, but everything from apples to spirea. Genus names are written in knowing the basic rules and applying them to everyday gar- italics or are underlined, and the first letter is capitalized. For dening leads to a better understanding of plants and how they example, Picea is the genus for spruce. are classified. Identification may be as simple as knowing that Species—A population of individual plants within a genus members of the mint family (Lamiaceae) have square stems. that are capable of interbreeding freely with one another. For (Rub a stem of oregano or dead nettle between your fingers example, Picea abies is the species for Norway spruce. as a test.) Or identification may be as complicated as deciding Other terms also are important in plant identification: among a series of choices that eventually lead to identification Specific epithet—The second word in a plant name. (The word of the plant’s genus and species. (This process is called “keying “species” refers to the plant, but the term “specific epithet” refers out,” and it will be explained in more detail later.) to the actual word in the name.) It is italicized, and the first let- You’ll be able to dazzle your family and friends by rattling ter is not capitalized. off names such as Liriodendron tulipfera (commonly known Variety—A subset of a species. Varieties are populations of as the tulip tree or tulip poplar and the current state tree of plants divided by geography and some significantly different Kentucky) by learning about plant identification. You’ll also characteristic. For example, Rudbeckia fulgida, the orange cone- be able to determine a plant’s cultural requirements, ultimate flower native to North America, is a desirable perennial that, size, flowering and fruiting habits, propagation methods, and compared to many Rudbeckias, is less susceptible to powdery common problems. Many insects and diseases are fairly host- mildew. The variety sullivantii has exceptional three- to four- specific; that is, they attack only certain species (and sometimes inch, bright yellow flowers. The popular cultivar ‘Goldsturm’ is only certain varieties within a species) or certain genera. When a more compact form of this variety. The word “variety” can be you know a plant’s genus and species, you can identify problems abbreviated as “var.”; it is not italicized. Subspecies (ssp.) often and make a diagnosis more easily, efficiently, and with more is used in Britain with the same meaning. certainty. In fact, the first step in diagnosing a sick plant is to Form—A naturally occurring characteristic that makes the identify the plant. plant different from other plants in the same population. For example, the pink-flowering dogwood, Cornus florida f. rubra, occurs naturally in its native habitat in the eastern United States, where it grows among the white-flowered form, which is more prominent. CHAPTER 02 Plant Identification Hybrids A hybrid is a cross between two varieties or species, whether of the same genus or two different genera. F1 hybrids, common among annual vegetables and flowers, are highly controlled and manipulated. They are a cross between two lines within a species, each of which has been selected and repeatedly inbred for specific traits. Hybrid names are written with an × between the genus and specific epithet. The latter word is made up, and often “media” is used. Some hybrids occur in nature, such as Arctostaphylos × media, which is a cross between kinnikinnick (A. uva-ursi) and the taller growing A. columbiana and is found where the two parents grow in close proximity. Hybridization is common in cultivation, as breeders look for better plants for our gardens. Sometimes, cultivated plants grow close enough together to cross on their own. ‘Eddie’s White Wonder’ is a cross between two native dogwood spe- cies: Cornus nuttallii and Cornus florida. ‘Arthur Menzies,’ an impressive winter-blooming evergreen shrub, was an accidental cross between Mahonia bealei and Mahonia lomariifolia. Occasionally, an intergeneric hybrid occurs. The commonly planted Leyland cypress was an accidental cross between two species found at a nursery in England. The parents are the Monterey cypress, Cupressus macrocarpa, and the Alaskan cedar, Chamaecyparis nootkatensis. The correct way to write an intergeneric hybrid is to put the × before the genus. Leyland cypress is written as × Cupressocyparis leylandii. (The two generic names were combined.) Cultivars The term cultivar is short for “cultivated variety.” These are plants within a species that have been selected especially for a particular characteristic and propagated—usually asexually—to continue this characteristic. Bigger blooms, better color, larger fruits, and more compact growth are a few reasons a plant may be selected. The cultivar name is written in plain text and set off by single quotes. Gardeners are familiar with cultivar names and often refer to plants by only the genus and cultivar, especially if the cultivar is the result of a hybrid cross. Thus we see Penstemon ‘Apple Blossom,’ Fuchsia ‘Santa Claus,’ and Rhododendron ‘PJM.’ Cultivars may arise from chance seedlings, selective breed- ing, or a sport (a spontaneous genetic change). The continuously blooming climbing rose ‘New Dawn’ was found as a sport of an old once-blooming climber, ‘Dr. W. van Fleet.’ Before 1959, cultivar names could be Latin or at least sound like it. Viburnum opulus ‘Roseum,’ the snowball viburnum, was named before 1959. After that, cultivars were named in modern languages, so you will find cultivars with Japanese, German, Dutch, or English names. 2-2  Plant Identification CHAPTER 02 For a while, the practice was to anglicize cultivar names that English speakers found difficult to pronounce (or that were difficult to market to English speakers). This practice not only was unfair to breeders but caused a great deal of confu- sion. Now, growers and nurseries are encouraged to use the correct names, whatever the language. Thus, for example, the well-known Penstemon ‘Garnet’ should be listed as Penstemon ‘Andenken an Freidrich Hahn.’ Keys are tools for classification and identification. When using a key, you move from general to more and more specific descriptions (and eventually to identification) by choosing among linked statements. These statements have descriptions, such as “leaves hairy” and “leaves smooth.” Choosing the state- ment that more correctly describes a specific plant leads to a progressive narrowing of choices until you arrive at the name of the plant. Keys are found in many plant identification books and on the Internet. Some include the whole range of flowering plant families; others cover only one genus, such as roses. The paired statements in a key may be lettered or numbered. Sometimes the two statements are separated by a lot of space, since there are even more choices below each statement. See Table 2.1 for a brief example of a key. Practicing Plant Identification Practice—as always—makes perfect. The more you use botanical names for plants, the more quickly you will remember them and the less self-conscious you’ll be when you say them. Here are some ways to learn and remember plant names: Say the names over and over, using any opportunity that comes along. Repeat the names of plants in your own garden, even when you are alone. Say aloud the names of plants you recognize in other gardens. Spend a little time each day on plant names. The names and characteristics of plants should become almost second nature. Table 2.1. Example of a key. I. Leaves opposite 1a. Leaves mostly less than 4 cm (15 ⁄ 8”) 2a. Leaf margins 3a. Leaf margins spiny-toothed Osmanthus delavayi toothed 3b. Leaf margins crenate* Euonymus fortunei 2b. Leaf margins entire Buxus sempervirens 1b. Leaves more than 4 cm Viburnum davidii II. Leaves alternate 1a. Leaves mostly less than 6 cm (23 ⁄ 8”) 2a. Stems armed (thorny) Pyracantha species 2b. Stems not 3a. Leaves oblanceolate* Pieris japonica armed 3b. Leaves ovate* Vaccinium ovatum 1b. Leaves greater than 6 cm 4a. Leaves ovate* Prunus lusitanica 4b. Leaves obovate* Prunus laurocerasus * Key: crenate = rounded scallops, oblanceolate = broad tip and tapering base, ovate = oval-shaped, obovate = oval-shaped with broadest part of leaf at the tip. 2-3 CHAPTER 02 Plant Identification Try to learn the meaning of the names so they make more sense to you. For example, Acer macrophyllum is the bigleaf maple (macro meaning “large” and phyllum meaning “leaf ”). Color also plays an important part in plant names. A few examples are Acer rubrum, or red maple, which incorporates the Latin “rub” for red; Symphoricarpos alba, or snowberry, which uses the Latin “alba” for white; and Ribes sanguineum, or red-flowering currant, which uses the Latin”sanguin” for blood. When you look at plants, note identifying features such as leaf shape and arrangement, growth habit, and flower or fruit appearance. All these aspects help in correct identification. Refer to Chapter 1 for illustrations. Practice plant identification while visiting arboretums, nurs- eries, and public gardens (enjoyable in itself ). These places often have plant tags or lists of plants. Practice using keys such as the one in Dichotomous Keys for the Arboretum Walk (https://www.uky.edu/hort/sites/www. uky.edu.hort/files/pages-attachments/treekeys.pdf ) Revised 01-2024