Grasses of Montana 1 GRASSES of MONTANA 13 December 2011
Grasses of Montana 1 GRASSES OF MONTANA 13 December 2011 Matt Lavin and Cathy Seibert, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana 59717 POACEAE (GRAMINAE) Annual or perennial, usually monoecious herbs. Stems terete, rarely flattened. Leaves basal and often cauline, alternate, linear, parallel-veined, entire, composed of a lower sheath enclosing the stem and a flat, inrolled, or folded blade. Inflorescence terminal, consisting of spikelets arranged in usually open to spike-like panicles, less commonly racemes or solitary spikes. Flowers often bisexual; each enclosed by a lemma and palea; petals and sepals reduced to 1- -6 small translucent scales (lodicules); stamens 1--6, ovary superior with 1--3 stigmas. Fruit a caryopsis, rarely an achene (as in Eragrostis and Sporobolus). The Poaceae includes about 10,035 species and 668 genera (Stevens, 2001 onward), making it one of the largest flowering plant families. Poaceae is distributed world-wide from deserts to tropical rain forests and from coastal saline areas to alpine and arctic tundra. It is one of the most economically important plant families and includes rice, wheat, barley, rye, corn, millet, and sorghum, as well as many forage, ornamental, and turf species. Poaceae is distinguished from other monocots by small flowers that are each enclosed by a lemma and palea. The flower, lemma, and palea comprise the grass floret. Florets alternate along opposites sides of a rachilla to form the grass spikelet, which is delimited by a basal pair of glumes (lemma-like but sterile bracts). Grasses show outstanding morphological diversity in the architecture of seed dispersal.
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