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

968 POACEAE/LEPTOCHLOA
notched), awnless or mucronate or with an awn 0.5–3.5(–11) mm long; anthers 0.2–1 mm
long; inflorescences not hidden.
4. Axils of inflorescence branches pilose; spikelets (2–)3–4 mm long; plants perennial _________ L. virgata
4. Axils of inflorescence branches glabrous; spikelets (3.5–)4–10(–12) mm long (5 mm or more
in most East TX specimens); plants annual.
5. Spikelets 5–10(–12) mm long, with 6–12 florets; lemmas (at least some) with an awn
0.5–1.5(–3.5) mm long (in L. fusca subsp. fascicularis) OR awnless or mucronate (in L.
fusca subsp. uninervia); inflorescences usually with ca. 8–35 branches; species widespread
in East TX ____________________________________________________________________ L. fusca
5. Spikelets (3.5–)4–5 mm long, with 4–7 florets; lemmas awnless or mucronate; inflorescences
usually with (20–)40–90 branches; species rare, if present, in East TX __________ L. panicoides
Leptochloa dubia (Kunth) Nees, (doubtful), GREEN SPRANGLETOP, TEXAS CROWFOOT. Tufted perennial;
culms 25–115 cm long, erect or ascending, unbranched above base; ligule a truncate
membrane with dense row of cilia, 1–1.5(–2) mm long; apical inflorescence exserted but some
inflorescences hidden in lower leaf sheaths (unique in the genus—Snow 1997); inflorescences
with (2–)7–15 unbranched, flexuous, loosely erect or spreading main branches; spikelets (4–)5–
12 mm long, usually with 3–8(–13) florets; lemmas usually 4–5 mm long; glumes and lemmas
awnless. Rocky slopes, loams, most typically on well-drained sites; widespread in w 2/3 of TX,
scattered further e; sc U.S. from MO s to TX w to CO and AZ, also CA and FL. Spring–fall.
[Diplachne dubia (Kunth) Scribn.] While this plant is valuable as forage, because of hydrogen
cyanide production in new growth after rains, caution is advised (Hilsenbeck in Powell 1994).
According to Snow (1997), this species is most likely to be confused with L. fusca subsp.
uninervia, which can have lemmas somewhat chopped off in appearance—however, that taxon
has shorter lemmas (1.8–3(–3.6) mm long), lacks hidden inflorescences, is an annual, and usually
grows in wet habitats. �
Leptochloa fusca (L.) Kunth, (brown, dusky), BEARDED SPRANGLETOP. Tufted annual; culms (15–)
50–100(–130) cm tall, erect to spreading and ascending; ligule a membrane, 2–7 mm long, lacerate
but not ciliate; inflorescences with ca. (3–)8–35 stiffly erect or erect-spreading branches;
glumes and lemmas awned or awnless. There has been significant nomenclatural confusion
and change regarding this taxon. Snow and Davidse (1998) proposed that the older (but obscure
and of somewhat doubtful application) name L. malabarica (L.) Veldkamp [Poa malabarica L.]
be rejected in favor of L. fusca. The Nomenclatural Committee for Spermatophyta (Brummitt
2000) recommended acceptance of the proposal. We are therefore following Snow and Davidse
(1998) and Snow (1998a) in using the name L. fusca for this species. Further, we are following
Snow (1998a) in treating the taxa formerly recognized (e.g., Gould 1975b; Diggs et al. 1999) as L.
fascicularis and L. uninervia as subspecies of L. fusca.
1. Upper glume (2.5–)3–4.2(–5) mm long; inflorescence branches 4–12(–22) cm long; lemmas lanceelliptic,
acute to acuminate, 2.5–4(–5) mm long, usually with awn 0.5–1.5(–3.5) mm long; inflorescence
base often enclosed in the uppermost leaf sheath; uppermost leaf blade often surpassing
panicle; mature lemmas often light with a dark spot below the middle __________ subsp. fascicularis
1. Upper glume � 3 mm long; inflorescence branches often only 3–6 cm long (sometimes longer);
lemmas obovate, blunt, 1.8–3(–3.6) mm long, awnless or abruptly mucronate; inflorescence base
usually not enclosed in the uppermost leaf sheath; uppermost leaf blade usually not surpassing
panicle; mature lemmas without a dark spot _______________________________________ subsp. uninervia
subsp. fascicularis (Lam.) N. Snow, (fascicled, clustered), BEARDED SPRANGLETOP, SALT MEADOW
GRASS, SALT SPRANGLETOP. Mud, sometimes alkaline or subsaline; Dallas, Grayson, (BRIT),
Bastrop, Bexar, Guadalupe, Orange, Travis (Snow 1997), Brazos, Jefferson, and Washington
(Turner et al. 2003) cos.; scattered throughout TX; scattered in s Canada and nearly throughout