Use these terms while you study your plants, collect data and make observations.
Architectural Features of Grasses
Awn/bristle: A slender, hair-like structure found on the spikelets of many grasses.
Blade: The upper portion of the leaf, which is divided from the sheath by the collar and the ligule.
Collar: The area on the outer side of the leaf where the blade and the sheath join.
Culm: The stem of a grass.
Florets: A small flower.
Glume: One of a pair of dry membranous bracts at the base of the spikelet of grasses.
Inflorescence: The part of a plant that consists of a cluster flower bearing stalks.
Internode: The part of a plant stem between two nodes.
Lemma: The outer bract that encloses the flower in a grass spikelet.
Ligule: The structure that clasps the stem at the junction of blade and sheath.
Node: The point on a plant stem from which the leaves or lateral branches grow.
Palea: The inner bract that encloses the flower in a grass spikelet.
Panicle: A branched cluster of flowers in which the branches are racemes.
Plant Architecture: Structures of the plant, leaves, stems, roots, and the patterns they take.
Raceme: A type of inflorescence that is unbranched and bears flowers having short stalks along the axis.
Shatter: When the seed head breaks apart, releasing seeds.
Sheath: The tubular portion of the leaf, which wraps around or encloses the stem.
Spike: An inflorescence consisting of a raceme of flowers growing directly from the stem.
Spikelet: A flowering structure common to grasses, where a reduced flower is encased in several protective structures.
Tiller: A shoot that arises from the base of the stem in grasses.
Other Important Terms
Adaptive Value: The ability of a new trait to add to an individual or species’ chances of survival.
Albino: No color: white
Gene Frequency: How often a gene appears within a population.
Genetic Engineering: Technology where DNA from one organism is placed into a different organism.
Genotype: The two specific alleles an individual has for a trait.
Model Organism: An organism chosen by scientists for study, usually based on characteristics such as short generation time, high reproductive rates, easily observed characteristics, and close relative relationship to other organisms.
Mutagenic Agent: Any substance that can change DNA, including UV radiation, asbestos, and certain chemicals.
Mutation: A change in DNA base pairs
Necrosis: Death of tissue.
Phenotype: The observable characteristics of an organism, as determined by its genetic makeup.
Selective Breeding: The process where humans control the reproduction of a species to favor certain desirable traits.
Serrated: Having notched or jagged edges.
Silent Mutation: A change in DNA that does not produce a change in the phenotype.
Variegated: Plants with a variety of colors on the same leaf.
Variation: The amount of diversity within a species or population.
Virescent: Not fully green as compared to the wild type.
Wild Type: Considered the typical phenotype for the species, considered “normal” when compared to new, possibly mutant traits.
