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

GYMNOPOGON/POACEAE
955
Glyceria septentrionalis Hitchc., (northern), FLOATING MANNA GRASS, EASTERN MANNA GRASS,
Plant glabrous; culms ca. 1–1.8 m tall, often rooting near base; ligule ca. 3–6(–10) mm long; leaf
blades usually 4–10 mm wide; inflorescence usually 18–40(–50) cm long, the branches short
and rigid. Wet areas, often in woods; Bowie, Brazos, Franklin, Trinity, and Robertson (TEX) cos.;
also n Gulf Prairies and Marshes; se Canada and e U.S. w to MN and TX. Mar–Jun. [Panicularia
septentrionalis (Hitchc.) E.P. Bicknell]
Glyceria striata (Lam.) Hitchc., (striated, striped), FOWL MANNA GRASS, NERVED MANNA GRASS.
Plant glabrous, often with short rhizomes; culms 0.4–0.9(–1.5) m tall, usually erect from decumbent
bases; ligule 1–4 mm long; leaf blades usually 2–8 mm wide, rarely wider; inflorescence
10–22(–25) cm long, typically with numerous slender, flexuous branches; spikelets ca. 2–4(–5)
mm long; lemmas usually 1.3–2(–2.5) mm long, glabrous or nearly so, the 7 veins usually quite
prominent; anthers 0.3–0.5(–0.9) mm long. Along streams, swamps, marshes, moist forest margins;
Bowie (BAYLU) and Lamar (Carr 1994) cos. in Red River drainage, also Bell (TAES), Travis,
and Washington (Turner et al. 2003) cos.; rare in e Edwards Plateau and Trans-Pecos; nearly
throughout s Canada and the U.S., also disjunct to the mountains of Mexico (Tucker 1996). Apr–
Aug. This species is variable morphologically, but the differences appear to be “a consequence
of environmental, rather than genetic, factors” (Barkworth ined.). It is reported as potentially
cyanogenic (Burlage 1968; Fuller & McClintock 1986). �
GYMNOPOGON P. Beauv. BEARD GRASS, SKELETON GRASS
Clumped perennials from rhizomes; culms nearly erect to decumbent; leaves cauline, distichous
(= 2-ranked), crowded; ligule minute, a fringed membrane or a rim of callus tissue, � 1
mm long; leaf blades flat, short, abruptly narrowed and � cordate at base, (resembling those of
some Panicum species); inflorescence a panicle, mostly ca. as wide as long or wider, with numerous
widely spreading to reflexed, spike-like branches (these alternate along the main axis
of the inflorescence), with small beards of hairs often present at base of inflorescence branches;
spikelets usually not overlapping, appressed, in 2 rows on 1 side of the slender, slightly flattened
branches, with 1(–2) perfect lower floret and 1 rudimentary upper floret (usually reduced to
only a naked or awned pedicel); disarticulation above the glumes; glumes subequal (upper
slightly longer), longer than the florets; lemma of fertile floret with an awn from the minutely
notched apex; palea often slightly longer than lemma.
AA C4 genus of ca. 15 species mostly of warm areas of the Americas, with 1 species from India
to Thailand (Smith 2003). The foliage is superficially similar to that of some Panicum species,
while the inflorescence is reminiscent of Chloris. The genus is related to Chloris, but
Gymnopogon can be distinguished by its 2-ranked leaves, alternate inflorescence branches,
glumes longer than the florets, and the essentially obsolete upper floret (Clayton & Renvoize
1986; Yatskievych 1999). (Greek: gymnus, naked, and pogon, beard, referring to the reduction of
the abortive flower to a bare awn, or to the naked prolongation of the rachilla in a number of
species) (subfamily Chloridoideae, tribe Cynodonteae)
REFERENCES: Smith 1971, 2003.
1. Branches of inflorescence bearing scattered spikelets usually to the base (the very base with a
spikelet); rudimentary floret with a distinct awn or sometimes reduced to only an awned pedicel;
rhizomes short, knotty or plant merely with a knotty base; lemma of fertile floret with awn 4–8
(–12) mm long __________________________________________________________________ G. ambiguus
1. Branches of inflorescence without spikelets in the basal 1/3 or more of their length (the very
base without a spikelet); rudimentary floret awnless, reduced to only a naked pedicel; rhizomes
elongate; lemma of fertile floret with awn 1–3(–4.5) mm long ____________________________ G. brevifolius