keys to the vascular plants of east texas - Botanical Research ...

1054 POACEAE/SETARIA
7. Lemma of upper (fertile) floret coarsely transversely wrinkled and rugose (use hand
lens or dissecting scope); species rare in East TX, known only from Harris, Jasper, Liberty,
and Walker cos. _____________________________________________________ S. corrugata
7. Lemma of upper floret finely rugose or smooth; including species widespread in East TX.
8. Bristles retrorsely scabrous (with down-pointing barbs visible with hand lens, the
free end of the barbs below (= proximal to) the attached end); inflorescence
branches in whorls; main inflorescence axis with short stiff hairs only __________ S. verticillata
8. Bristles antrorsely scabrous (with up-pointing barbs visible with hand lens, the
free end of the barbs above the attached end); inflorescence branches not in welldefined
whorls; main inflorescence axis with long spreading hairs in addition to
short stiff hairs.
9. Inflorescences often nodding or drooping from near the base (particularly at
maturity); upper surface of leaf blades with sparse to often dense, long, papillabased
hairs (can also be scabrous); species not currently known from East TX
(included because of probability of occurrence) _____________________________ S. faberi
9. Inflorescences erect or nodding near the tip, but not from near the base; upper
surface of leaf blades glabrous to scabrous, without long, papilla-based hairs
(note: there may be long hairs along leaf margins); including species widespread
in East TX.
10. Panicles often lobed or interrupted, purple or yellow, often large and heavy,
to 30 cm long; spikelets (2.5–)2.6–3.4 mm long, disarticulating between the
lower and upper florets, the fertile floret deciduous from glumes and lemma
of sterile floret; lemma of fertile floret smooth and shiny or nearly so _________ S. italica
10. Panicles not lobed or interrupted, usually green, usually 10(–15) cm or less
long; spikelets ca. 1.6–2.6 mm long, falling entire (disarticulation below the
glumes); lemma of fertile floret finely rugose ____________________________ S. viridis
6. Plants perennial; bristles mostly 1(–2) below each spikelet; inflorescences not extremely
dense in appearance, much of the axis visible.
11. Spikelets 2.8–3.4 mm long; leaf blades � densely villous on both upper and lower
surfaces; species mainly of w TX, disjunctly known in East TX only from Anderson
Co. ________________________________________________________________ S. villosissima
11. Spikelets 1.8–2.8 mm long; leaf blades scabrous or variously pubescent but not villous;
species widespread in East TX.
12. Panicles very narrow, ca. 5 mm wide (excluding bristles), 2–8(–12) cm long; culms
usually branching well above base (at some upper nodes); spikelets 1.8–2.1 mm
long; herbage dark green; species known in East TX only from Bexar and Wilson
cos. near extreme sw margin of area _______________________________________ S. texana
12. Panicles usually 10–70 mm wide, 6–35 cm long; culms usually not branching
above base; spikelets 1.9–2.7 mm long; herbage dark or light green; including
species widespread in s and w parts of East TX.
13. Mature spikelets 1.9–2.1(–2.3) mm long, strongly inflated and appearing
nearly globose; palea of lower floret nearly as long as lemma, ovate; leaf
blades, at least some, 7–15 mm wide; species known in East TX only from
Bexar Co. on extreme sw margin of area _________________________ S. macrostachya
13. Mature spikelets usually 2.1–2.8 mm long, neither strongly inflated nor globose;
palea of lower floret usually one-half to three-fourths as long as lemma,
lanceolate; leaf blades variable in width (see couplet 14 below); species widespread
in s and w parts of East TX.
14. Leaf blades narrow, usually 2–9 mm wide; panicles usually cylindric, not
tapered, usually 6–15 cm long; bristles mostly 4–15 mm long, ascending
____________________________________________________________ S. leucopila