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

DICHANTHELIUM/POACEAE 905
that this species appears related to D. oligosanthes but differs in having wider leaf blades, larger
spikelets, and bearded culm nodes.
Dichanthelium scabriusculum (Elliott) Gould & Clark, (somewhat rough), TALL SWAMP PANIC
GRASS, WOOLLY ROSETTE GRASS. Culms usually 90–150 cm tall, the nodes neither swollen nor
bearded, glabrous or only slightly hairy, often with a glandular band below the node; leaf
sheaths glabrous or with some pubescence, but not velvety pubescent, narrowed at top, mottled
with pale spots; leaf blades 7–15 mm wide, glabrous or with some pubescence on lower surface,
but not velvety pubescent; spikelets 2.2–2.9 mm long. Low, wet, often shaded sites, sandy soils;
scattered in East TX in Jasper (Ajilvsgi 5921, BRIT), Hardin, Leon, Tyler (TAES—annotated by S.
Hatch), Anderson (SBSC), Austin, Bowie, and Robertson (Turner et al. 2003) cos.; e U.S. from NY
s to FL w to TX. May(–Jul), also fall. [Panicum scabriusculum Elliott] This species is somewhat
similar to D. scoparium but has leaf sheaths glabrous or at least without velvety pubescence
and nodes not bearded. According to Freckmann and Lelong (2003a), D. scabriusculum possibly
hybridizes with D. clandestinum, D. dichotomum, and D. aciculare.
Dichanthelium scoparium (Lam.) Gould, (broom-like), VELVET ROSETTE GRASS, VELVETY PANIC
GRASS. Culms coarse, 80–155 cm tall, often conspicuously stout (usually 2–5 mm thick), the
nodes often swollen, usually conspicuously bearded with a glabrous, glandular band below the
beard; lower culm internodes and lower leaf sheaths and blades usually with velvety pubescence;
leaf sheaths narrowed at top; leaf blades (7–)9–25(–30) mm wide; spikelets 2.2–2.8 mm
long, often purplish at base. Sandy woods and low areas, often in disturbed sites; widespread in
East TX, mainly in Pineywoods and Post Oak Savannah; also n Gulf Prairies and Marshes; e U.S.
from NY s to FL w to KS and TX. May–Jun, also fall. [Panicum scoparium Lam.] If not for the
velvety pubescence, this species would resemble D. scabriusculum (Gould 1975b).
Dichanthelium scoparium possibly hybridizes with D. acuminatum and D. dichotomum
(Freckmann & Lelong 2003a).
Dichanthelium sphaerocarpon (Elliott) Gould, (spherical-fruited), ROUND-SEED ROSETTE GRASS,
ROUND-SEED PANIC, ROUND-SEED DICHANTHELIUM, ROUND-FRUIT PANIC GRASS. Culms 20–50 cm
tall; ligule minute or apparently absent; blades of larger culm leaves 6–13(–14) mm wide, usually
cordate at base, slightly auricled-clasping, ciliate only near the base, the margins white and
cartilaginous; inflorescence axis glabrous; spikelets 1.4–1.8(–2) mm long. Sandy soils, shaded or
open areas; widespread in e 1/2 of TX, scattered further w; se Canada (Ont.) and widespread in
e U.S. w to KS and TX. Late Mar–Jun, again late summer–fall. [Panicum sphaerocarpon Elliott]
The plants are similar to glabrous forms of D. acuminatum var. lindheimeri but differ in having
a minute or absent ligule. This species also sometimes superficially resembles D. strigosum. It
can, however, be distinguished by the glabrous inflorescence axis and leaf blades ciliate only
near the base (versus inflorescence axis usually with spreading hairs and leaf blades ciliate to
beyond the middle in D. strigosum). Dichanthelium sphaerocarpon hybridizes with several other
species, including D. acuminatum, D. laxiflorum, and D. polyanthes (Gould & Clark 1978;
Freckmann & Lelong 2003a). This species has sometimes been treated as including D. polyanthes
as a variety (var. isophyllum or var. polyanthes); Gould (1975b) indicated that this and D.
polyanthes, which he treated as D. sphaerocarpon var. polyanthes, seem to completely intergrade.
Dichanthelium strigosum (Muhl.) Freckmann, (strigose, with stiff bristles), ROUGH-HAIR RO-
SETTE GRASS, CUSHION-TUFTED PANIC GRASS. Culms ca. 45 cm or less tall, not branched above
base; leaves mostly basal (only 2–4 leaves on culm); leaf sheaths glabrous or ascending pilose;
leaf blades 3–8 mm wide, ciliate to beyond the middle; inflorescence axis with spreading hairs;
spikelets 1.1–2.1 mm long, often purplish or brownish purple; glumes ca. 1/3–1/2 as long as
spikelet. Moist pinelands, bogs, other low areas, sandy soils. The infraspecific taxa of this species
have been variously treated as varieties, subspecies, or species (e.g., Turner et al. 2003). Until
a thorough revision of the group is carried out, we are recognizing the infraspecific taxa at the