17. Agrostis L. (bent grass)
Plants annual or perennial, sometimes with rhizomes or
stolons, forming dense to loose tufts or clumps. Flowering stems erect or
ascending, sometimes from spreading bases, glabrous. Leaf sheaths rounded on
the back to slightly keeled, glabrous or somewhat roughened, the ligule often
somewhat irregular along the margin. Leaf blades flat or with inrolled margins,
glabrous or roughened. Inflorescences open to dense panicles with strongly
ascending to spreading branches, erect or slightly arched. Spikelets somewhat
flattened laterally, disarticulating above the glumes (and sometimes also at
the base of the inflorescence), with 1 perfect floret and without additional
staminate or sterile florets. Glumes about as long as to somewhat longer than
the rest of the spikelet, similar in shape and size (the lower glume sometimes
slightly shorter than the other glume), somewhat keeled, lanceolate, narrowed
or tapered to a sharply pointed tip, awnless. Lemma membranous at maturity,
lanceolate, bluntly to sharply pointed at the tip, sometimes the tip with 1 or
3 minute teeth, rounded on the back, awnless or less commonly short‑awned
(the short awn attached below the middle of the back or the long slender awn
attached toward the tip in A. elliottiana), (3)5‑nerved, glabrous
or roughened, the base short‑hairy. Palea absent or up to 2/3 as long as
the lemma, membranous, nerveless or 2‑nerved. Stamens 1 or more commonly
3. Fruits narrowly oblong‑elliptic in outline. About 200–220 species,
nearly worldwide, mostly in temperate regions.
Several species of Agrostis are cultivated as turf
grasses for lawns. Some of the species can be difficult to distinguish.