Eragrostis airoides |
Eragrostis lutescens |
|
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darnel lovegrass |
six-weeks love grass |
|
Habit | Plants perennial; cespitose, with innovations, without rhizomes, not glandular. | Plants annual; tufted, without innovations. |
Culms | 30-110 cm, erect, glabrous below the nodes. |
(2)6-25 cm, usually erect, sometimes decumbent, glabrous, with elliptical, yellowish, glandular pits below the nodes. |
Sheaths | glabrous or pilose, hairs to 5 mm; ligules 0.1-0.2 mm; blades 8-22 mm long, (1)2-4(5) mm wide, flat to folded, glabrous abaxially, scabridulous adaxially. |
with elliptical glandular pits, sparsely hairy at the throat, hairs to 2 mm; ligules 0.2-0.5 mm, ciliate; blades 2-12 cm long, 1-3 mm wide, flat to involute, abaxial surfaces scabridulous, bases with glandular pits. |
Panicles | 18-70 cm long, 3-25 cm wide, diffuse, ovate; primary branches 4-20 cm, appressed or diverging 10-70° from the rachises, naked basally; pulvini glabrous; pedicels 2.4-11 mm, divergent. |
terminal, 4-10(15) cm long, 0.5-2 cm wide, narrowly elliptic, contracted, dense; primary branches alternate, usually appressed, occasionally diverging to 30° from the rachises, rachises and branches with glandular pits; pulvini glabrous; pedicels 1.4-10 mm, appressed or divergent. |
Spikelets | 1.3-2 mm long, 0.8-1.8 mm wide, ovate to lanceolate, plumbeous, with 1-3 florets; disarticulation acropetal, in the rachilla below the florets, glumes deciduous; rachilla prolonged above the terminal floret. |
3.6-7.5 mm long, 1.2-2 mm wide, narrowly ovate, light yellowish, occasionally mottled with reddish-purple, with 6-11(14) florets; disarticulation acropetal, paleas persistent. |
Glumes | lanceolate to ovate, membranous; lower glumes 0.8-1 mm; upper glumes 1.1-1.4 mm; lemmas 0.8-1.2 mm, ovate, membranous, plumbeous, keels and lateral veins inconspicuous, apices obtuse; paleas 0.8-1.2 mm, membranous, bases not projecting beyond the lemmas, apices obtuse; anthers 3, 0.3-0.5 mm, purplish. |
subequal, ovate to lanceolate, hyaline; lower glumes (0.7)0.9-1.4 mm; upper glumes 1.2-1.8 mm; lemmas 1.5-2.2 mm, ovate, subhyaline, stramineous, veins greenish and conspicuous, apices acute; paleas 1.2-2 mm, hyaline, keels scabridulous, apices obtuse; anthers 3, 0.2-0.3 mm, purplish. |
Caryopses | 0.4-0.5 mm, ovoid, reticulate, reddish-brown. |
0.5-0.8 mm, pyriform except slightly flattened adaxially, smooth, light brown. |
Comm | .). |
|
2n | = 36 (Davidse, pers. |
= unknown. |
Eragrostis airoides |
Eragrostis lutescens |
|
Distribution |
TX |
AZ; CA; CO; ID; NM; NV; OR; WA |
Discussion | Eragrostis airoides is a South American species that, in the Flora region, is known only from roadsides and disturbed sites in Brazos County, Texas. It is an enigmatic species, often treated as Sporobolus brasiliensis (Raddi) Hack., which it resembles in its chromosome base number of x = 9 and caryopsis morphology, but its frequent possession of spikelets with more than 1 floret and its mode of spikelet disarticulation argue for its retention in Eragrostis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eragrostis lutescens grows on the sandy banks of streams and lakes and in moist alkaline flats of the western United States at 300-2000 m. It has not been reported from Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 103. | FNA vol. 25, p. 79. |
Parent taxa | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Eragrostis | Poaceae > subfam. Chloridoideae > tribe Cynodonteae > Eragrostis |
Sibling taxa | ||
Name authority | Nees | Scribn. |
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