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

DICHANTHELIUM/POACEAE 887
20. Internodes, particularly the lower ones, long-hairy, the hairs
spreading to ascending or appressed; leaf blades with at least
one surface pubescent; spikelets densely to sparsely pilose;
upper glume usually without an orange or purple spot at base
________________________________________________________ D. ovale
20. Internodes glabrous to variously hairy; leaf blades glabrous or
variously pubescent; spikelets glabrous to pubescent; upper
glume with OR without an orange or purple spot at base.
21. Spikelets usually 2.7–4 mm long, 1.7–2.4 mm wide; lower
glume similar to upper glume; upper glume usually with
an orange or purple spot at base; leaf blades usually 4–12
(–15) mm wide _________________________________ D. oligosanthes
21. Spikelets 2.4–2.8(–3) mm long, 1.2–1.8 mm wide; lower
glume different than upper, usually thinner and more
weakly veined; upper glume usually without an orange or
purple spot at base; leaf blades usually 2–7(–8) mm wide
__________________________________________________ D. aciculare
14. Leaf blades (at least larger ones) usually 13–40 mm wide.
22. Leaf blades velvety-tomentose or puberulent beneath, glabrous or puberulent
above; spikelets 2.4–2.8 mm long _____________________________________ D. scoparium
22. Leaf blades usually neither velvety-tomentose nor puberulent beneath (or if so,
spikelets 3.4–4 mm long), often glabrous on both surfaces; spikelets 2.4–4 mm long.
23. Spikelets broadly elliptic to obovate, turgid, with heavy broad veins; leaf
blades usually 4–12(–15) mm wide; upper glume usually with an orange or
purple spot at base ___________________________________________ D. oligosanthes
23. Spikelets narrowly elliptic to narrowly obovate, neither turgid nor strongly
veined; leaf blades 8–40 mm wide; upper glume variable in color, yellowish
green to greenish or purplish, but usually without an orange or purple spot
at base.
24. Leaf sheaths, at least lower ones, papillose-hispid with spreading hairs,
constricted at apex; culms with 5–10 cauline leaves _____________ D. clandestinum
24. Leaf sheaths glabrous to puberulent or softly villous, not constricted
apically; culms with 4–6 cauline leaves.
25. Spikelets 2.4–3.2 mm long, 1.1–1.3 mm wide; leaf blades usually
� 10 cm long ________________________________________ D. commutatum
25. Spikelets (2.9–)3.3–3.9 mm long, 1.6–2 mm wide; leaf blades mostly
8–20 cm long ____________________________________________ D. latifolium
6. Spikelets 0.8–2.4 mm long.
26. Leaf blades glabrous or nearly so, except near base or on margins.
27. Leaves mostly basal, the culms with only 2–4 leaves above the rosette, the basal
leaves relatively similar to those of the culm; plants branched only at the base
(culms unbranched).
28. Leaf sheaths glabrous or with ascending hairs 2 mm or less long; margins of
leaf blades with papillose-based cilia __________________________________ D. strigosum
28. Leaf sheaths pilose with widely spreading to slightly reflexed hairs 2–3.5 mm
long; margins of leaf blades usually ciliate at least on the basal half but the cilia
not papillose-based _______________________________________________ D. laxiflorum
27. Leaves well-distributed along the culm (culms with 3–14 leaves), the basal ones
different (shorter and/or wider) than those of the culm; plants often branched
above the base.