70. Setaria P. Beauv. (foxtail grass)
(Rominger, 1962)
Plants with C4 photosynthesis, annual or
perennial, usually forming tufts. Flowering stems erect or ascending, often
spreading at the base, glabrous or less commonly hairy at the nodes. Leaf
sheaths glabrous or hairy, the ligule a short membrane with a fringe of hairs
along the margin. Leaf blades flat or sometimes loosely twisted, glabrous or roughened
and/or hairy. Inflorescences dense, narrow panicles with very short branches of
few to many spikelets, these usually reduced to clusters of spikelets and the
inflorescences then appearing as cylindrical spikes. Spikelets elliptic to
ovate‑elliptic in outline, each subtended by 1–20 roughened bristles,
without a cuplike ring or knoblike disk at the base, shed individually, leaving
the persistent bristles, disarticulating below the glumes (above the glumes in S.
italica). Lower glume triangular to ovate, bluntly to sharply pointed at
the tip, awnless, 3‑ or 5‑nerved. Upper glume not inflated or
saclike at the base, elliptic‑ovate, rounded to bluntly pointed at the
tip, awnless, 3–9‑nerved, glabrous. Lowermost floret sterile or
staminate, the palea usually well developed and conspicuous (sometimes reduced
and inconspicuous in S. viridis), the lemma about as long as the rest of
the spikelet, rounded to bluntly pointed at the tip, awnless, 3–9‑nerved,
glabrous. Fertile (perfect) floret with the lemma about as long as the rest of
the spikelet, elliptic‑ovate, rounded or bluntly pointed at the tip,
awnless, nerveless, with noticeable, fine cross‑wrinkles on the surface
(except in S. italica), glabrous, mostly dull, light green to pale
yellow, thickened and hard (usually somewhat bonelike) at maturity, the margins
also thick, wrapped around the palea and fruit, including the tip (after
flowering). Paleas with noticeable, fine cross‑wrinkles on the surface
(except in S. italica), glabrous, dull, thickened and hard (usually
somewhat bonelike) at maturity. Fruits oblong‑elliptic in outline. About
125 species, nearly worldwide, mostly in tropical and warm‑temperate
regions.