The Language Of Flowers
Flowers play an essential role in reproduction. The color and fragrance of a flower attract pollinators, which play a vital part in a plant’s reproductive process. The color and fragrance also attract people, who in turn widen the plant’s distribution by planting it in other localities and even on other continents. Here are some useful terms to know about flower parts and related structures.
|Axis||An elongated, central, supporting structure running through the leaf or stem|
|Calyx||A collective term for the group of sepals (leaflike structures) that enclose a flower bud and encircle the petals when the flower is open|
|Corolla||A collective term for petals|
|Corymb||A short, broad, flat-topped flower cluster with individual flower stalks emerging at different points along an axis; the outermost flowers in a corymb open first|
|Cyme||A short, broad flower cluster that always has a flower on the tip of the axis; in a cyme, the central flowers open first|
|Inflorescence||The flowering part of a plant, usually used to denote a flower cluster or arrangement of flowers on an axis|
|Panicle||An open flower cluster, sometimes pyramid shaped, with no terminal flower on the tip of the axis; a branched raceme|
|Pedicel||A stalk of one flower in a multiflowered inflorescence|
|Peduncle||A stalk of a solitary flower or inflorescence|
|Perianth||The collective term for the corolla (petals) and calyx (sepals) together|
|Petal||A set of modified floral leaves, usually white or colored, that surround the stamens and pistils|
|Pistil||The “female” organ of a flower, composed of three parts—ovary, style, and stigma|
|Raceme||A simple, elongated stem with flowers on short stalks; flowers on the lowest part of the stem bloom first|
|Sepal||A leaflike flower structure that encloses a flower bud and encircles the petals when a flower is open|
|Spike||A simple, elongated stem with stalkless flowers or flower heads; flowers on the lowest part of the stem bloom first|
|Stamen||The “male” organ of the flower, composed of an anther containing pollen, most often on a filament|
|Umbel||A cluster of flowers with stalks of almost equal length attached to a common point; individual flowers form a flat or nearly flat top|
A Closer Look At Leaves
Leaves, although not as important as flowers in terms of classification, nonetheless provide essential clues for plant identification. When examining a plant, look at the way its leaves are arranged. The leaves can be opposite (arranged in pairs along the stem, as in plants of the mint family) or alternate (unpaired, occurring in an alternating pattern along the stem, as in plants of the borage family). Whorled leaves encircle a plant’s stem, a pattern that can be seen in many plants of the lily family. The leaves of some plants, such as mullein and plantain, form what is called a basal rosette—a cluster of leaves arranged in a circular pattern on the ground at the base of the flower stalk.
The structure of a leaf is an important element of plant identification. Leaves can be simple (consisting of only one part) or compound (composed of multiple parts, or leaflets). In the rose family, for example, five rounded leaf lets attached to a stalk make up a single compound leaf. Plants in the carrot and ginseng families also have compound leaves.
The leaflets of palmately compound leaves are all attached to the leaf’s petiole at one point. A pinnately compound leaf is composed of leaflets arranged on opposite sides of an axis. Even pinnate leaves have an even number of leaflets, odd pinnate leaves have an odd number.
After determining whether a plant’s leaves are compound or simple and how they are arranged on the plant’s stem, note the shape and texture of the leaves. Leaves can be glabrous (hairless) or pubescent (hairy); the edges (or margins) can be serrate (toothed) or entire (untoothed). And the leaves can be round, oval, heart-shaped, lancelike, or one of many other shapes.
Leaf Shape And Margins
An herb leaf’s shape and margins are defining characteristics associated with the plant’s genus and species.
The Language Of Leaves
Along with roots and stems, leaves are a basic organ of plants. Their primary function is photosynthesis: the process by which a leaf uses energy from sunlight to process water and carbon dioxide into carbohydrates, such as sugars, which the plant uses as food. The following terms are used to describe leaves, leaf shapes, and leaf structures.
|Basal||At the base (as in a basal rosette of leaves); arising at the base of the stem|
|Bract||A reduced or modified leaf located close to the base of a flower or inflorescence|
|Compound leaf||A leaf having two or more distinct leaflets|
|Dissected||Divided deeply into many narrow segments|
|Elliptic||Having the approximate shape of an ellipse|
|Entire||Leaf margins with no teeth or lobes|
|Lanceolate||Lance-shaped, several times longer than wide; widest at the base and tapering toward the tip|
|Linear||Narrow and flat with parallel sides, like a blade of grass|
|Lobe||A segment of a leaf, especially when rounded|
|Node||The place on a stem from which leaves or branches originate|
|Oblong||Somewhat rectangular; having greater length than width and a rounded, not squared, base and tip|
|Obovate||Shaped like a hen’s egg, but having the wider end toward the tip|
|Ovate||Similar to obovate, but with the wider section at the base of the leaf, where it is attached to the stem|
|Palmate||With numerous leaf divisions radiating from one point at the base of the leaf|
|Petiole||The stalk of a leaf blade or a compound leaf|
|Pinnate||Leaf divisions (leaflets) arranged along the axis or stalk|
|Serrate||With sharp teeth, pointed forward|
|Sessile||Having no stalk|
|Simple||A leaf with a blade in one piece, not compound; sometimes lobed|
|Stipule||A modified leaf part, usually paired, found at the base of the petiole in certain plant families, such as the rose family|
|Trifoliolate||Leaves having three leaflets|
Examining Fruits And Seeds
A fruit is the fertilized, ripened ovary of a flower. It contains the plant’s seeds, fertilized ovules that hold the genetic material for a new plant. While some fruits are juicy, tasty structures such as apples, tomatoes, and plums, others are merely hard, dry seedpods.
Simple fruits ripen from an ovary with one pistil and can take many forms. Examples of dry simple fruits include an achene (buckwheat), a capsule (poppy), a caryopsis (grass), a cypsela (daisy), a follicle (milkweed), a legume (pea), a nut (acorn), a samara (elm), a schizocarp (parsley), and a silique (mustard plant). Examples of fleshy simple fruits include a berry (tomato), a drupe (plum), and a pome (apple).
Other classifications of fruits include multiple fruits (formed from a cluster of flowers, as in a pineapple), aggregate fruits (formed from single flowers with multiple pistils that are not fused together, as in a raspberry), and accessory fruits (not originating from an ovary but from tissue outside of the carpel, as in a strawberry). Fruits and seeds provide important foods and medicines and can be vital for plant identification.
Fruits And Seeds
A fruit and its seeds contain the genetic material for a new plant. These are a few of their many possible forms.
The Anatomy Of Stems And Roots
A plant’s stem offers structural support and serves as a transport and storage system for nutrients and water. Along the stem, nodes or swellings indicate where leaves, buds, or branches will arise. A stolon sprouts from the main stem and grows horizontally along the surface of the soil or just below the ground, referred to by gardeners as a runner.
Stems can take many forms, both above and below the soil. A tuber such as a potato, for example, is actually a thickened underground stem, usually with numerous buds (eyes). Similarly, a rhizome, although often mistaken for a root, is actually an underground part of the main stem with roots attached. A bulb is a shortened stem covered by leaf bases or scales that enclose fleshy leaves.
Roots are underground structures that anchor and support a plant, absorb nutrients and water, and store food for the plant. Some plant roots are composed of a main axis with smaller roots coming off the primary root, known as secondary roots. Other plants, such as corn, have a fibrous root system that consists of many fine, threadlike roots. A taproot is a fleshy root that grows downward, sometimes swelling into a storage organ that is eaten, such as a beet or carrot. Roots of an individual plant can grow out several feet beyond the stem, thus competing for resources such as water and fertilizer. That’s why plant spacing, depending on the species grown, is important in the garden or farm field.