Eragrostis mexicana

(Hornem.) Link
Common names: Mexican lovegrass
Treatment appears in FNA Volume 25. Treatment on page 78.

Plants annual; cespitose, without innovations. Culms 10-130 cm, erect, sometimes geniculate, glabrous, sometimes with a ring of glandular depressions below the nodes. Sheaths sometimes with glandular pits, pilose near the apices and on the collars, hairs to 4 mm, papillose-based; ligules 0.2-0.5 mm, ciliate; blades 5-25 cm long, 2-7 (9) mm wide, flat, abaxial surfaces glabrous, adaxial surfaces scabridulous, occasionally pubescent near the base. Panicles (5) 10-40 cm long, (2) 4-18 cm wide, ovate, rachises angled and channeled; primary branches 3-12 (15) cm, solitary to whorled, appressed or diverging to 80° from the rachises; secondary branches somewhat appressed; pulvini glabrous; pedicels 1-6 (7) mm, almost appressed to narrowly divergent, stiff. Spikelets (4) 5-10 (11) mm long, 0.7-2.4 mm wide, ovate to linear-lanceolate, gray-green to purplish, with 5-11 (15) florets; disarticulation acropetal. Glumes subequal, 0.7-2 (2.3) mm, ovate to lanceolate, membranous; lemmas 1.2-2.4 mm, ovate, membranous, glabrous or with a few hairs, gray-green, lateral-veins evident, often greenish, apices acute; paleas 1-2.2 mm, hyaline, keels scabrous, apices obtuse to truncate; anthers 3, 0.2-0.5 mm, purplish. Caryopses 0.5-0.8 (1) mm, ovoid to rectangular-prismatic, laterally compressed, shallowly to deeply grooved on the adaxial surface, striate, reddish-brown, distal 2/3 opaque. 2n = 60.

Distribution

Wash., Del., Oreg., Wis., Iowa, N.Dak., Fla., N.Mex., Tex., Idaho, B.C., Ont., Nev., Colo., Calif., Ind., Maine, Ill., Ariz., Md., Mass., Utah, S.C.

Discussion

Eragrostis mexicana grows along roadsides, near cultivated fields, and in disturbed open areas, at 100-3000 m. It is native to the Americas, its native range extending from the southwestern United States through Mexico, Central and northern South America, to Argentina. Within the Flora region, it has been introduced beyond its native range, often becoming an established part of the flora.

Selected References

None.

Key

1 Spikelets ovate to oblong in outline, 1.5-2.4mm wide; lower glumes 1.2-2.3 mm long; sum of the spikelet width and lower glume length 2.7-4.7 mm; culms and sheaths sometimes with glandular depressions Eragrostis mexicana subsp. mexicana
1 Spikelets linear to linear-lanceolate, 0.7-1.4 wide; lower glumes 0.7-1.7 mm long; sum of the spikelet width and lower glume length 1.5-3.1 mm; culms and sheaths without glandular depressions Eragrostis mexicana subsp. virescens

"decumbent" is not a number.

... more about "Eragrostis mexicana"
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Obtuse (?) +  and Truncate (?) +
Paul M. Peterson +
(Hornem.) Link +
1 (?) +  and 3 (?) +
multiple +, , +  and single +
not +  and glabrous +
keeled +  and rounded +
pseudopetiolate +  and branching +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
not pseudopetiolate +
5 cm50 mm <br />0.05 m <br /> (25 cm250 mm <br />0.25 m <br />) +
pubescent +  and glabrous +
involute +, folded +  and flat +
2mm;7mm +
not disarticulating +
not spikelike +
pubescent +  and glabrous +
opaque +  and reddish-brown +
compressed +, ovoid +  and rectangular-prismatic +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
triangular +  and dome--shaped +
sometimes longer +
membranous +
Mexican lovegrass +
branched +, simple +  and rooting +
geniculate +
10 cm100 mm <br />0.1 m <br /> (130 cm1,300 mm <br />1.3 m <br />) +
not woody +
Wash. +, Del. +, Oreg. +, Wis. +, Iowa +, N.Dak. +, Fla. +, N.Mex. +, Tex. +, Idaho +, B.C. +, Ont. +, Nev. +, Colo. +, Calif. +, Ind. +, Maine +, Ill. +, Ariz. +, Md. +, Mass. +, Utah +  and S.C. +
not waisted +
capillary +
pistillate +  and staminate +
sometimes longer +
5 +  and 11 +
round +  and compressed +
reduced +
persistent +  and deciduous +
shorter or longer +
subtending +
ovate +  and lanceolate +
subequal +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
membranous +
papillose-based +
uncinate +
0 cm0 mm <br />0 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
paniculate +  and racemose +
hollow +  and solid +
not absent +
(1)3(5)-veined +
with a few hairs +  and glabrous +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
membranous +
sometimes longer +
ciliate +  and ciliolate +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
membranous +
inconspicuous +
concealed +  and prominent +
2 +  and 1 +
persistent +
2-keeled +
0.1 cm1 mm <br />0.001 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
open +  and simple +
10cm +  and 40cm +
4 cm40 mm <br />0.04 m <br /> (18 cm180 mm <br />0.18 m <br />) +
7 cm70 mm <br />0.07 m <br /> (?) +
0.1 cm1 mm <br />0.001 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
dry +  and fleshy +
solitary +  and whorled +
15 cm150 mm <br />0.15 m <br /> (?) +
diverging;appressed +
3 cm30 mm <br />0.03 m <br /> (12 cm120 mm <br />0.12 m <br />) +
spikelike +
channeled +  and angled +
gray-green +  and purplish +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
1 +  and 60 +
ovate +  and linear-lanceolate +
0.7mm +  and 2.4mm +
1 (?) +  and 3 (?) +
compound +  and simple +
2 (?) +  and 3 (?) +
Gramineae +
Eragrostis mexicana +
Eragrostis +
species +
membranous +
7 +  and 13 +
rhizomatous +  and stoloniferous +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +  and synoecious +