Aristida schiedeana

Trin. & Rupr.
Common names: Single threeawn
Treatment appears in FNA Volume 25. Treatment on page 323.

Plants perennial; cespitose. Culms 30-120 cm, erect, unbranched. Leaves basal and cauline, pale green, sometimes glaucous; sheaths longer or shorter than the internodes, glabrous except at the summit; collars densely to sparsely pilose or glabrous; ligules less than 0.5 mm; blades 8-30 cm long, 1-2 mm wide, usually flat, often curled at maturity. Inflorescences paniculate, 10-30 cm long, (4) 8-26 cm wide; rachis nodes with straight hairs, hairs to 0.8 mm; primary branches 6-16 cm, abruptly spreading to divaricate, stiff to lax, with axillary pulvini, usually not spikelet-bearing below midlength. Spikelets appressed, rarely spreading. Glumes 1 (3) -veined, brown or purple at maturity, acuminate; lower glumes 6-13 mm; upper glumes equaling or to 4 mm shorter than the lower glumes; calluses 0.8-1.2 mm; lemmas 10-15 (17) mm, terminating in a strongly twisted, 2-4 mm awnlike beak, junction with the awns not conspicuous; awns not disarticulating at maturity; central awns 5-12 mm, markedly bent near the base; lateral awns absent or to 1 (3) mm, erect; anthers 1.2-2.2 mm, brownish. Caryopses 6-8 mm. 2n = 22, 44.

Distribution

Calif., Ariz., N.Mex., Tex.

Discussion

Aristida schiedeana grows on rocky slopes and plains, generally in pinyon-juniper, oak, or ponderosa pine communities. Plants from the southwestern United States and northern Mexico belong to A. schiedeana var. orcuttiana (Vasey) Allred & Valdes-Reyna, in which the lower glumes are usually glabrous and longer than the upper glumes, and the collar and throat are usually glabrous. Aristida schiedeana var. schiedeana grows in Mexico, Guatemala, Nicaragua, and Honduras, and has puberulent, equal glumes and pilose collars and throats.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number."elongated" is not a number.

... more about "Aristida schiedeana"
3 +  and 1 +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
Kelly W. Allred +
Trin. & Rupr. +
not disarticulating +
1 (?) +  and 3 (?) +
straight +
ascending +  and spreading +
not conspicuous +
keeled +  and rounded +
coiled +, disarticulating +  and twisted +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
straight +
awnlike +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
8 cm80 mm <br />0.08 m <br /> (30 cm300 mm <br />0.3 m <br />) +
1mm;2mm +
spikelike +
well-developed +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
non-radiate +  and radiate +
0.5 cm5 mm <br />0.005 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
glabrous +  and pilose +
Single threeawn +
30 cm300 mm <br />0.3 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
not woody +
Calif. +, Ariz. +, N.Mex. +  and Tex. +
large +  and small +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
purple +  and brown +
subtending +
acuminate +
straight +
0 cm0 mm <br />0 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
10cm +  and 30cm +
pale green +
cauline +  and basal +
scabridulous +
fusiform +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
coriaceous +
indistinguishable +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
inconspicuous +
0.6 cm6 mm <br />0.006 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
concealed +  and prominent +
2 +  and 1 +
concealing +
0 +  and 1/2 +
dry +  and fleshy +
6 cm60 mm <br />0.06 m <br /> (16 cm160 mm <br />0.16 m <br />) +
not prolonged +
1 (?) +  and Anatomy (?) +
1 +  and 60 +
1 (?) +  and 3 (?) +
triangular +  and dome--shaped +
2 (?) +  and 3 (?) +
Gramineae +
Aristida schiedeana +
Aristida +
species +
membranous +
0-4 mm +  and equaling +
plant +  and cespitose +
aquatic +  and terrestrial +