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

888 POACEAE/DICHANTHELIUM
29. Hairs of ligule and adjacent hairs (= pseudoligule), at least some, 2–6 mm long
_____________________________________________________________ D. acuminatum
29. Hairs of ligule 2 mm or less long.
30. Plants robust, the culms usually 90–150 cm tall; spikelets 2.2–2.4 mm long;
main inflorescences 10–21 cm long; leaf sheaths often mottled with pale
spots ____________________________________________________ D. scabriusculum
30. Plants relatively smaller, the culms 15–80 cm tall; spikelet length various
but often less than 2.2 mm long; main inflorescences 2–12 cm long; leaf
sheaths not mottled.
31. Blades of larger culm leaves 6–30 mm wide, abruptly narrowed to subcordate
or cordate basally, slightly auricled-clasping, with white cartilaginous
margins.
32. Leaf blades (at mid-culm) 15–30 mm wide, with evident veins, the
uppermost leaf blades usually 10–15 cm or more long; culms erect
or nearly so, usually with 4–7 cauline leaves; inflorescences � 1/2 as
wide as long; species of the Pineywoods and Post Oak Savannah
_____________________________________________________ D. polyanthes
32. Leaf blades (at mid-culm) 6–13(–14) mm wide, with obscure veins,
the uppermost leaf blades usually 3–9 cm long; culms decumbent
or ascending, usually with 3–4(–6) cauline leaves; inflorescences >
1/2 as wide as long; species widespread in e 1/2 of TX and scattered
to the w _____________________________________ D. sphaerocarpon
31. Blades of larger culm leaves 3–10(–14) mm wide, narrowed or rounded
basally, not auricled, without white cartilaginous margins (except with
white margins in D. tenue).
33. Spikelets 1–1.3 mm wide; leaf sheaths often (but not always) villous
with long, spreading, sometimes papilla-based hairs; culm
nodes not bearded _______________________________________ D. aciculare
33. Spikelets 0.6–1 mm wide; leaf sheaths glabrous to pubescent, but
without long spreading hairs; culm nodes bearded OR not so.
34. Culm internodes and leaf sheaths usually puberulent, but
sometimes glabrous; culm nodes not bearded; leaf blades 2.5–
6(–8) mm wide; spikelets ± attenuate basally (= tapering to a
narrow base) _____________________________________ D. portoricense
34. Culm internodes and leaf sheaths (except the margins) glabrous;
culm nodes often (but not always) with a beard of
spreading hairs; leaf blades 5–15 mm wide; spikelets not attenuate
basally.
35. Leaf blades of lower culm commonly more than 5 cm long
or more than 4.5 mm wide; spikelets 1.5–2.4 mm long;
culms (20–)40–80(–100) cm tall, usually > 1 mm thick __ D. dichotomum
35. Leaf blades of lower culm usually 5 cm or less long and
4.5(–6) mm or less wide; spikelets 1.1–1.7 mm long; culms
to only 40(–55) cm tall, usually � 1 mm thick.
36. Margins of leaf blades thin, green; spikelets glabrous
or sparsely puberulent; culms reclining or weakly erect,
usually with 4–9 leaves _________________________ D. ensifolium
36. Margins of leaf blades with cartilaginous, usually whitish
border; spikelets puberulent, often densely so;
culms erect from geniculate base, with 3–4 leaves _______ D. tenue