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

850 POACEAE/BRACHYELYTRUM
OK. Mostly Jul–Aug, with a much shorter flowering period than B. hirsuta. [B. hirsuta var.
pectinata (Feath.) Cory, B. hirsuta subsp. pectinata (Feath.) Wipff & S.D. Jones, Chondrosum
pectinatum (Feath.) Clayton] While Wipff and Jones (1996), Jones et al. (1997), and Wipff
(2003d) recognized this taxon at the subspecific level and Kartesz (1999) recognized it as a variety,
we are following Roy and Gould (1971), whose biosystematic investigation supports its recognition
as a separate species. Hatch (2002) also treated B. pectinata as a distinct species. Even
though hybridization can occur where the two grow together (Wipff 2003d), they differ in numerous
morphological characters and are usually easily distinguished in the field. According to
Gould (1979), “… the morphological uniformity of this species [B. pectinata] contrasts strikingly
with the variability observed in populations of plants of B. hirsuta.” Further, molecular evidence
(e.g., Columbus et al. 2000) does not support combining the two species. m/278
Bouteloua repens (Kunth) Scribn. & Merr., (creeping), SLENDER GRAMA. Perennial; culms to 65
cm long, erect to decumbent, sometimes rooting at lower nodes; inflorescence branches usually
4–9(–12), ca. 9–20 mm long, along 1 main axis terminating a leafy culm; branch axis extending
2–6 mm beyond attachment point of terminal spikelet, but not beyond the terminal spikelet
apex; lemma of fertile floret mucronate or short-awned; single rudimentary floret usually welldeveloped,
usually staminate. Grasslands and open brushy areas; Bexar (TAES) and Travis (Carr
2002a) cos. near sw margin of East TX; mainly South TX Plains; AZ, NM, and TX. Apr–Dec. The
single known Travis Co. collection (Sexton, s.n., COA) was from a degraded Blackland Prairie
site and represents the northern limit of this species (Carr 2002a).
Bouteloua rigidiseta (Steud.) Hitchc., (stiff-awned), TEXAS GRAMA, MESQUITE GRASS. Perennial 50
cm or less tall; inflorescence branches 6–8(–10), ca. 0.8–1.6 cm long (to end of spikelets), along 1
main axis terminating a leafy culm; branch axis 4–8 mm long, forked or trifurcate at apex, extending
slightly beyond base of terminal spikelet but not extending needle-like beyond the
spikelet apex; lemma of fertile floret 3-awned; rudimentary floret(s) reduced, sometimes to an
awn column, 3-awned. Grasslands; widespread in TX; AR, LA, OK, and TX. Mar–Oct; reported
to be one of the earliest warm season grasses to flower (Wipff 2003d). Details of the life history
and population biology of this species were studied by Miller and Fowler (1994) and Miller et
al. (1995). According to Wipff (2003d), while sometimes abundant, this species “has little value
as a forage grass.” m/278
Bouteloua trifida Thurb., (three-parted), RED GRAMA, THREEAWN GRAMA. Perennial to 40 cm tall;
inflorescence branches 3–8 per main axis, to 2(–2.5) cm long, slender and usually appressed to
main axis; axis of inflorescence branches not extending beyond spikelets, ending in a spikelet
but without terminal, rudimentary, axis-like spikelet. Grasslands, typically in relatively dry areas;
Bell, Bexar, Hays, Travis (BRIT), Brazos, and Comal (Turner et al. 2003) cos. in the w part of
East TX; mainly w 2/3 of TX; sw U.S. from TX w to CA. Apr–Nov. [Chondrosum trifidum (Feath.)
Clayton] This species is drought resistant. It is sometimes mistaken for an Aristida “because of
its delicate cespitose growth habit and purplish, 2-awned spikelets” (Wipff 2003d).
Bouteloua uniflora Vasey, (one-flowered), NEALLEY’S GRAMA, ONE-FLOWER GRAMA. Perennial to
60 cm tall; inflorescence branches usually 15–70(–83) per main axis, (5–)7–9 mm long, with 1
(–2) spikelet; branch axis extending ca. 3–5 mm beyond attachment point of spikelet but not
beyond the spikelet apex. Rocky calcareous soils; Bexar and Goliad (TAES) cos. near s margin of
East TX, also disjunct to Grimes Co. (S.U. Smith 60, 1996, TAES) to the n; scattered mainly in w
1/2 of TX; in the U.S. known only from TX and one collection from Utah (Wipff 2003d); also
Coahuila, Mexico. Jul–Nov.
BRACHYELYTRUM P. Beauv. SHORT HUSK
AA C3 genus of three species (Saarela et al. 2003) of woodland grasses, two in e North America
and one in e Asia. Species limits in the genus have been controversial, with some authorities