Glossary For Grasses

Annual. A plant that completes its entire life cycle (from seed to seed) in one year.

Anther. The pollen-producing part of the stamen, located at the tip of a slender stalk (the filament). Sometimes called a pollen sac.

Aw n . A slender bristlelike or needlelike appendage extending from the lemma or glume. Awns may be short and barely conspicuous or they may be many inches long, contributing significantly to the beauty and translucency of grass flowers.

Biennial. A plant which completes its life cycle (from seed to seed) in two years. Biennial species usually produce only foliage during the first year. They flower and produce seed in the second year.

Biome. The plants and animals in an ecosystem.

Blade. The flat, expanded portion of the leaf above the sheath. The blade may be reduced or modified in various ways, or be absent altogether.

Bract. A general term for any structure that represents a modified leaf; most commonly used to refer to reduced, leaflike structures associated with inflorescences. In grasses the glumes, lemmas, and paleas are considered bracts.

Calcareous. Containing much higher than average amounts of calcium or lime. Calcareous habitats are often characterized by the presence of limestone and are typically alkaline.

Caryopsis. The single-seeded fruit typical of members of the grass family, Poa-ceae. A caryopsis, often called a grain, does not open at maturity and is typically hard and dry.

Cespitose, caespitose. Tufted, clump-forming. Grasses with a cespitose growth habit are often referred to as bunchgrasses.

Circumboreal. Around the northern regions.

Clonal cultivar. A plant that requires asexual propagation to retain its unique characteristics.

Crown. The base of the plant.

Culm. The aboveground stem of a grass plant. Culms are usually upright but may be horizontal.

Deciduous. Shedding or falling off. In grasses, plants that go dormant for part of the year, eventually replacing old growth with new.

Dioecious. Of a species with male and female flowers on separate plants.

Ecotype. A population adapted to a particular set of environmental conditions.

Endemic. Native and restricted to or occurring only in a particular place. Sometimes used in a broader sense to mean native, not introduced or naturalized.

Endosperm. An energy reserve in the form of starch, present in the grains of grasses and in the seeds of many other types of plants.

Evergreen. Remaining green or living throughout the year.

Filament. The threadlike stalk which bears the anther at its tip. The filament and anther comprise a stamen.

Floret. In grasses, the collective term for an individual flower plus the enclosing palea and lemma.

Forb. A broad-leaved flowering plant, as opposed to the grasses, sedges, and rushes.

Genotype. A group of organisms having the same genetic constitution.

Germ. The embryonic grass plant.

Glaucous. Covered with a thin layer of wax. Glaucous plant parts often appear blue-gray, blue-green, or gray-green. The term is also used to denote such coloration.

Glume. A bract located at the base of a grass spikelet. Typically there are two glumes associated with each spikelet.

Grain. The single-seeded fruit of true grasses, Poaceae, technically called a caryopsis.

Herbaceous. Lacking true woody (secondary) tissue.

Honeydew. A syrupy waste product produced by mealybugs and aphids

Inflorescence. The flowering portion(s) of a plant, complete with any associated bracts.

Internode. The section of the culm occurring between two consecutive nodes.

Lemma. The lower, outer bract in the grass floret.

Ligule. A thin membranous ridge or small row of hairs located at the juncture of the sheath and blade on the side facing the culm. The function of the ligule is uncertain, although it may serve to keep rain from entering the sheath. The variation in ligules is often very important in the botanical identification of grasses. It is of lesser value to gardeners in distinguishing between cultivated varieties.

Lodicule. One of two small scalelike structures usually present at the base of the ovary in the flowers of true grasses, Poaceae. The lodicules swell prior to pollination, forcing the palea and lemma apart and exposing the flower. Lodicules may represent the vestiges of sepals or petals, which are otherwise lacking in grass flowers.

Ovary. The enlarged lower portion of the female organ, containing the ovule or ovules.

Ovule. An immature, unfertilized seed, located within the ovary.

Monoculture. A population or planting consisting of only one type of plant.

Node. A point on an axis (usually a culm or stem) where a leaf or branch is attached.

Palea. The upper, inner bract in the grass floret.

Panicle. An inflorescence having spikelets attached at the ends of stalks that branch from the rachis (main axis).

Perennial. A plant which lives for more than two years.

Perigynium (plural perigynia). A saclike, sometimes inflated structure enclosing the female flower or ovary in members of the sedge family, Cyperaceae, especially the genus Carex.

Provenance. In an ecological context, the origin of individual plants or a group of plants. This is distinct from the native range of a plant species. Provenance may also refer to plants of garden origin.

Raceme. An inflorescence having individual spikelets attached to the unbranched rachis (main axis) by short stalks.

Rachis. The main axis of an inflorescence.

Rame. In grasses, a type of raceme with repeating pairs of sessile and pedicellate spikelets, as found in Andropogon and Schizachyrium.

Rhizomatous. Spreading by rhizomes.

Rhizome. An underground horizontal stem.

Sheath. The lower part of the leaf, originating at a node, which clasps or encircles the stem. In true grasses, Poa-ceae, the sheath usually has overlapping margins. In sedges, Cyperaceae, the sheath is usually fused around the stem.

Shoot. A stem, or any portion of the plant derived from stem tissue.

Spike. An inflorescence having individual spikelets without stalks, attached directly to the unbranched rachis (main axis).

Spikelet. In grasses, a small spike, consisting of one or more florets attached to a small central axis, together with the basal bracts called glumes.

Sport. An individual showing marked variation from the normal type.

Stamen. The male organ of a flower, consisting of a slender stalk (filament) and the pollen-producing anther.

Stigma. The pollen-receiving structure. The stigma may be located directly at the top of the ovary, or may be separated from the ovary by a short stalk called the style.

Stolon. An aboveground horizontal stem.

Stoloniferous. Spreading by stolons.

Style. A short stalk projecting from the top of the ovary, usually terminating in a feathery stigma which receives pollen.

Tepal. A flower part that cannot be distinguished as either a sepal or a petal.

Terminal. Located at the tip or top end.

Tussock. A thick tuft.

Umbel. A type of inflorescence in which all flowering branches arise from a central point.

Utricle. A saclike, sometimes inflated structure enclosing the female flower or ovary in members of the sedge family, Cyperaceae. This term may also be used to refer to the saclike structure and the enclosed fruit.

Wo ody. Having well-developed secondary tissue, as is present in trees and shrubs.

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