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

842 POACEAE/BOTHRIOCHLOA
REFERENCES: Gould 1953, 1957a, 1959b, 1967; Shinners 1956b; Celarier & Harlan 1958; Heslop-
Harrison 1961; de Wet 1968; de Wet & Harlan 1966, 1970b; Allred 1981, 2003g; Allred & Gould
1983; Vega 2000.
1. Inflorescences usually pinkish purple or brownish at maturity; pedicelled spikelets about as long
as sessile spikelets.
2. Inflorescence axis shorter than branches, the inflorescence thus appearing nearly digitate;
lower glume of sessile spikelets without a glandular pit; species a pernicious weed overly
abundant in much of East TX __________________________________________________ B. ischaemum
2. Inflorescence axis usually longer than branches, the inflorescence thus not appearing digitate;
lower glume of sessile spikelets with OR without a conspicuous glandular pit; species
rare in East TX __________________________________________________________________ B. bladhii
1. Inflorescences usually whitish silvery or light tan (or in one species rare in East TX purplish or
brownish); pedicelled spikelets conspicuously shorter than sessile spikelets.
3. Sessile spikelets 4.5–7.5 mm long; awn of lemma 18–30(–35) mm or more long; lower glume of
sessile spikelet with OR without a glandular pit; culm nodes with OR without a conspicuous
ring of spreading to ascending, white hairs; species limited to the w and s margins of East TX.
4. Inflorescence axis 5–15+ cm long; inflorescences usually with 9 or more branches; culm
nodes with a conspicuous ring of spreading to ascending, white hairs 1–4 mm long _____ B. barbinodis
4. Inflorescence axis 0.6–4.5 cm long; inflorescences usually with 3–8 branches; culm nodes
glabrous or minutely puberulent _________________________________________________ B. hybrida
3. Sessile spikelets � 4.5 mm long; awn of lemma 18 mm or less long; lower glume of sessile
spikelet usually without a glandular pit (except in the rare B. bladhii); culm nodes without a
conspicuous ring of spreading to ascending, white hairs; including species widespread
throughout East TX.
5. Sessile spikelets awnless or with awns 6 mm or less long ____________________________ B. exaristata
5. Sessile spikelets with awns 8–18 mm long.
6. Inflorescences purplish or brownish; hairs subtending sessile spikelets only about 1/4
as long as the spikelets, so sparse as to not obscure the spikelets _____________________ B. bladhii
6. Inflorescences usually whitish silvery or light tan; hairs subtending sessile spikelets at
least 1/2 as long as the spikelets, abundant enough to somewhat obscure the spikelets.
7. Panicles 4–12(–14) cm long; sessile spikelets ovate; glumes blunt; leaves often clustered
at the base of the culms; culms usually less than 2 mm thick _______________ B. laguroides
7. Panicles 9–20 cm long; sessile spikelets narrowly ovate to lanceolate; glumes acute;
leaves evenly distributed on the culms; culms 2–4 mm thick ________________ B. longipaniculata
Bothriochloa barbinodis (Lag.) Herter, (bearded at nodes), CANE BEARD GRASS. Culms usually
60–120 cm tall; inflorescences included to long-exserted, usually with numerous branches, the
main inflorescence axis usually longer than branches; sessile spikelets 4.5–7.5 mm long, the
lower glume pitted or unpitted; lemma awn of sessile spikelet 20–30(–35) mm long. Sandy or
rocky limestone soils. Mostly May–Oct. Turner et al. (2003) cited Bell, Bexar, Caldwell, Guadalupe,
Hays, and Travis cos. on the w margin of East TX and Brazos Co. (cultivated?) further e
(they did not recognize varieties); w part of East TX s and w throughout the w 2/3 of TX; w U.S.
from CA e to OK and TX, also FL and SC. The county distribution map does not distinguish
varieties. This species has an interesting amphitropical distribution, being found in both North
America and s South America (Allred 1981). While some authorities (e.g., Kartesz 1999; Allred
2003g) do not recognize varieties, we are following Hatch (2002) in recognizing the variation at
the varietal level based on the usually distinct morphology.
1. Lower glume of most sessile spikelets without a glandular pit or depression _______________ var. barbinodis
1. Lower glume of most sessile spikelets with a glandular pit or depression (like a conspicuous
“pin-hole” in the surface of the glume) ______________________________________________ var. perforata