Poaceae
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Authority
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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Family
Poaceae
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Scientific Name
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Description
Family Description - Fls perfect or sometimes unisexual, 1–many in distichously organized spikelets, each spikelet typically with a pair of subopposite small bracts (glumes) at the base and one to several or many florets alternating on opposite sides of an often zigzag axis (the rachilla) above the glumes; each floret typically consisting of a pair of subopposite enclosing or subtending scales (the lemma and palea), two or three much smaller scales (the lodicules) above these, and the stamens and pistil; midvein of the lemma often excurrent as a dorsal or terminal awn; palea placed with its back to the rachilla, typically with 2 main veins, generally enfolded by the lemma, rarely suppressed; lowest floret sometimes represented by an empty or staminate, glume-like sterile lemma, the spikelet then usually with a single perfect terminal fl; stamens most often 3, sometimes 6, rarely more, seldom only 1 or 2, typically exserted at anthesis and the plants wind-pollinated, but sometimes included and the plants selfed; anthers elongate, basifixed but so deeply sagittate as to appear versatile; ovary superior, unilocular, bicarpellate or less often tricarpellate, accordingly with 2 or 3 often large and feathery stigmas; ovule solitary, subapical to basilateral, orthotropous to hemitropous or almost anatropous; fr, called a caryopsis or grain, usually tightly enclosed by the persistent lemma and palea, indehiscent, usually dry, the seed-coat usually adnate to the pericarp; embryo basilateral, peripheral to the endosperm, complex in structure, with an enlarged lateral cotyledon (the scutellum); herbs or seldom somewhat woody plants, without secondary thickening, the culms (flowering stems) terete (seldom flattened) and usually with hollow internodes; lvs distichously or rarely spirally arranged, but not 3-ranked, with a usually open sheath and a parallel-veined, typically narrow and elongate blade, often with a pair of small auricles at the base of the blade, and commonly with a membranous ligule adaxially at the juncture of sheath and blade, or the ligule sometimes composed of hairs, or wanting; spikelets arranged in a determinate or mixed secondary infl that most commonly has the form of a panicle but is sometimes spike-like or raceme-like. 600/10,000. The term rame is here used for an unbranched infl that bears both sessile and pedicellate spikelets. The arrangement of genera of grasses into subfamilies and tribes is in a state of flux. Many of the characters now being used are microscopic. The key to genera here presented (largely written by Richard Pohl) is artificial. The sequence of genera in the text is based mainly on that of Clayton and Renvoize, Genera Graminum, 1986. Sclerochloa dura (L.) P. Beauv., a native of s. Europe, is intr. at scattered stations in w. U.S. and in O., Mich., Ind., Ill., and Mo., and may be expected elsewhere in our range. Not very closely related to any of our genera, it falls between the first two alternatives of Group IV in the key, having only one obvious spike, as in the second alternative, but having the spikelets secundly arranged along two sides of the trigonous rachis, as in the first alternative. It is a tufted low annual, mostly under 2 dm, with broad, rounded, prominently 5-nerved lemmas. The persistent style-base forms a short beak on the grain.
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Common Names
The grass family