Eriochloa acuminata

(J. Presl) Kunth
Common names: Southwestern cupgrass
Synonyms: Eriochloa lemmonii var. gracilis Eriochloa gracilis
Treatment appears in FNA Volume 25. Treatment on page 513.

Plants annual; cespitose. Culms 30-120 cm, erect or decumbent, sometimes rooting at the lower nodes; internodes glabrous or with scattered hairs; nodes glabrous or pilose. Sheaths some¬ times conspicuously inflated, glabrous or pubescent; ligules 0.2-1.2 mm; blades 5-12 (18) cm long, (2) 5-12 (16) mm wide, linear, flat or folded, straight or lax, glabrous or sparsely pubescent adaxially. Panicles 7-16 cm long, 1-6 cm wide, loosely contracted; rachises scabrous or hairy; branches 5-20, 1-5 cm long, 0.4-0.6 mm wide, appressed to divergent, pubescent, sometimes setose, not winged, with 20-36 spikelets, spikelets mostly in unequally pedicellate pairs, solitary distally; pedicels 0.1-1 mm, hairy. Spikelets 3.8-5 (6) mm long, 1.1-1.4 mm wide, lanceolate to ovate. Lower glumes absent; upper glumes equaling the lower lemmas, lanceolate to ovate, hairy, 5 (7) -veined, acuminate to acute, unawned or awned, awns to 1.2 mm; lower lemmas 3.6-5 mm long, 1.1-1.4 mm wide, lanceolate to ovate, setose, 5 (7) -veined, acuminate to acute, unawned; lower paleas absent; anthers absent; upper lemmas 2.3-3.3 mm, 0.7-0.9 times as long as the lower lemmas, indurate, elliptic, rounded, 5-veined, awned, the awns 0.1-0.3 mm; upper paleas indurate, blunt, rugose. 2n = 36.

Distribution

Md., Nev., Okla., Miss., Tex., La., Utah, Calif., Tenn., N.Y., Ark., Ariz., Ill., Ga., Ky., Fla., Mo., N.C., S.C., Va., N.Mex.

Discussion

Eriochloa acuminata is native to the southern United States and northern Mexico, but has become established outside this region. It may hybridize with E. lemmonii, from which it differs in its lack of lower paleas, upper glumes and lower lemmas with level veins, and narrower, glabrous or sparsely pubescent leaf blades.

There are two varieties of Eriochloa acuminata, differing as shown in the key below. Both grow in Mexico as well as the United States.

Selected References

None.

Key

1 Spikelets 4-6 mm long, long-acuminate or tapering to a short awn Eriochloa acuminata var. acuminata
1 Spikelets 3.8-4 mm long, acute Eriochloa acuminata var. minor

"decumbent" is not a number."elongated" is not a number."-0.9timesaslongasthelowerlemmas" is not declared as a valid unit of measurement for this property.

... more about "Eriochloa acuminata"
anatomy +  and kranz +
Robert B. Shaw +, Robert D. Webster +  and Christine M. Bern +
(J. Presl) Kunth +
1 (?) +  and 3 (?) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
divergent +  and parallel +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
disarticulating +  and pseudopetiolate +
straight +
5 cm50 mm <br />0.05 m <br /> (12 cm120 mm <br />0.12 m <br />) +
pubescent +  and glabrous +
folded +, flat +  and linear +
5mm;12mm +
1cm +  and 5cm +
setose +  and pubescent +
spikelike +
0.4mm;0.6mm +
not developed +
terete +  and compressed +
sometimes longer +
Southwestern cupgrass +
decumbent +  and erect +
30 cm300 mm <br />0.3 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
well-developed +
Md. +, Nev. +, Okla. +, Miss. +, Tex. +, La. +, Utah +, Calif. +, Tenn. +, N.Y. +, Ark. +, Ariz. +, Ill. +, Ga. +, Ky. +, Fla. +, Mo. +, N.C. +, S.C. +, Va. +  and N.Mex. +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
unequal +
membranous +
uncinate +
bracteate +  and ebracteate +
solid +  and hollow +
with scattered hairs +  and glabrous +
cauline +  and basal +
coriaceous +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
membranous +
inconspicuous +
3.6mm +  and 5mm +
acuminate +  and acute +
1.1mm +  and 1.4mm +
complex +  and simple +
concealed +  and prominent +
pilose +  and glabrous +
2 +  and 5 +
2 +  and 1 +
pedicellate +
7cm +  and 16cm +
subterranean +
1 cm10 mm <br />0.01 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
dry +  and fleshy +
hairy +  and scabrous +
elongate +
pubescent +  and glabrous +
inflated +
in triplets +  and paired +
0.38 cm3.8 mm <br />0.0038 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
subterranean +
20 +  and 36 +
unisexual +  and bisexual +
lanceolate +  and ovate +
1.1mm +  and 1.4mm +
1 (?) +  and 3 (?) +
fused +  and free +
2 (?) +  and 3 (?) +
plumose +
dome--shaped +  and triangular +
Eriochloa lemmonii var. gracilis +  and Eriochloa gracilis +
Eriochloa acuminata +
Eriochloa +
species +
membranous +
acuminate +  and acute +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.33 cm3.3 mm <br />0.0033 m <br />) +
not pronounced +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +