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

DICHANTHELIUM/POACEAE 889
26. Leaf blades sparsely to densely pubescent or pilose over one or both surfaces.
37. Culms usually with only 2–4 leaves (most leaves at base of plant), unbranched; leaf
blades with margins coarsely ciliate to beyond the middle ____________________ D. strigosum
37. Culms with more than 3 leaves (most leaves not at base of plant), often branched;
leaf blades with margins not ciliate to beyond the middle.
38. Spikelets 0.8–2.1 mm long.
39. Spikelets 0.8–1.1 mm long, puberulent to subglabrous; culms delicate,
0.3–0.8 mm thick; plants of bogs, wetland pine savannahs, and other wet
habitats ___________________________________________________ D. wrightianum
39. Spikelets 1.1–2.1 mm long, variously pubescent; culms delicate or not so;
plants of wet to dry habitats.
40. Spikelets 1.1–2.1 mm long; leaf sheaths glabrous or with hairs 3 mm
or less long _____________________________________________ D. acuminatum
40. Spikelets 1.8–2.4 mm long; leaf sheaths with hairs usually more than 4
mm long _____________________________________ D. ovale subsp. praecocious
38. Spikelets 2.1–2.4 mm long.
41. Leaf sheaths with widely spreading or reflexed hairs 2–6 mm long _____ D. ovale subsp.
villosissimum
41. Leaf sheaths with appressed to ascending or spreading hairs ca. 2 mm
long or less.
42. Culm internodes glabrous or slightly hairy; culm nodes glabrous or
slightly hairy ___________________________________________ D. scabriusculum
42. Culm internodes definitely hairy; culm nodes usually with a dense ring
of hairs.
43. Culm nodes with a broad conspicuous glabrous region in addition
to (below) a ring of hairs; culms usually 80–155 cm tall, stout
(usually 2–5 mm thick) ___________________________________ D. scoparium
43. Culm nodes lacking a broad glabrous region; culms usually 80 cm
or less tall, slender (� 2 mm thick)
44. Ligule (1–)1.5–6 mm long; spikelets not attenuate basally _________ D. ovale
44. Ligule absent or less than 1 mm long; spikelets ± attenuate
basally _______________________________________ D. consanguineum
Dichanthelium aciculare (Desv. ex Poir.) Gould & C.A. Clark (bristle-like), NEEDLE-LEAF ROSETTE
GRASS, NARROW-LEAF PANIC GRASS. Plant 15–75 cm tall; culms glabrous or variously hairy, but
the nodes usually not bearded; leaves with lower sheaths usually sparsely to moderately villous,
the upper sheaths and blades glabrous or variously hairy; leaf blades usually 2–7(–8) mm
wide; panicles not contracted (and branches not appearing one-sided) or panicles contracted
(and branches appearing one-sided); spikelets 1.7–2.8(–3) mm long. Sandy woods, prairies; e U.S.
from MD s to FL w to MO, OK, and TX, also MN. Apr–Jun, also late summer–fall. Freckmann
and Lelong (2003a) noted that this species can hybridize with D. acuminatum, D.
consanguineum, D. dichotomum, D. ovale, and D. portoricense, which can “apparently lead to
some intergradation with these species.” This emphasizes the complexity encountered in
Dichanthelium. According to Gould (1975b), relatively glabrous plants of D. aciculare [treated
by him as D. angustifolium] resemble D. dichotomum (but D. aciculare in general has larger
spikelets and more pubescent herbage). The variation within D. aciculare has variously been
given no formal recognition (e.g., Allred & Gould 1978; Gould & Clark 1978) or recognized at
the varietal, subspecific (Freckmann & Lelong 2003a), or specific levels (e.g., Lelong 1986). Because
the variants are not well-separated geographically, we are following Wipff and Jones
(1994 [1995]) and Hatch (2002) in recognizing varieties. Larry Brown (pers. comm.) notes that
there are East TX plants intermediate between var. aciculare and var. angustifolium. Brown