Aristida purpurea var. wrightii

(Nash) Allred
Common names: Wright's threeawn
Synonyms: Aristida wrightii
Treatment appears in FNA Volume 25. Treatment on page 333.

Culms 45-100 cm. Blades 10-25 cm, involute or flat. Panicles (12) 14-30 cm; primary branches usually erect, without axillary pulvini, stiff, straight, lower nodes associated with 2-10 spikelets. Glumes tan to brown, fading to stramineous. Lower glumes 5-10 mm; upper glumes 9-16 mm; lemmas 8-14 mm long, narrowing to 0.2-0.3 mm wide; awns (8) 20-35 mm long, 0.2-0.3 mm wide at the base, lateral awns usually subequal to the central awn, rarely 1-3 mm. 2n = 22, 44, 66.

Distribution

N.Mex., Tex., Colo., Utah, Calif., Okla., Ariz., Nev.

Discussion

Aristida purpurea var. wrightii grows on sandy to gravelly hills and flats from the southwestern United States to southern Mexico. It is the most robust variety of A. purpurea, and has dark, stout awns and long panicles. It may be confused with var. nealleyi, which has narrower lemmas and awns and a light-colored panicle, but it also intergrades with var. purpurea and var. parishii. Aristida purpurea forma brownii (Warnock) Allred & Valdes-Reyna refers to plants with short central awns and lateral awns that are only 1-3 mm long.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

66 +, 44 +  and 22 +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.1mm;0.8mm +
Kelly W. Allred +
(Nash) Allred +
not disarticulating +
divaricate +
1 (?) +  and 3 (?) +
8 cm80 mm <br />0.08 m <br /> (?) +
straight +
2 cm20 mm <br />0.02 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
not conspicuous +
1.3 cm13 mm <br />0.013 m <br /> (14 cm140 mm <br />0.14 m <br />) +
0.2mm;0.3mm +
keeled +  and rounded +
coiled +, disarticulating +  and twisted +
spreading +  and appressed +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
straight +
0 cm0 mm <br />0 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
4 cm40 mm <br />0.04 m <br /> (25 cm250 mm <br />0.25 m <br />) +
scabridulous +
flat +  and involute +
10 cm100 mm <br />0.1 m <br /> (25 cm250 mm <br />0.25 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
spikelike +
well-developed +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
tan +  and chestnut +
0.6 cm6 mm <br />0.006 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
non-radiate +  and radiate +
pilose +  and glabrous +
Wright's threeawn +
erect +  and ascending +
45 cm450 mm <br />0.45 m <br /> (100 cm1,000 mm <br />1 m <br />) +
not woody +
N.Mex. +, Tex. +, Colo. +, Utah +, Calif. +, Okla. +, Ariz. +  and Nev. +
large +  and small +
thread-like +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
tan +  and brown fading +
subtending +
acute +  and acuminate +
unequal +
straight +
3 cm30 mm <br />0.03 m <br /> (?) +  and 30 cm300 mm <br />0.3 m <br /> (?) +
2 cm20 mm <br />0.02 m <br /> (12 cm120 mm <br />0.12 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
cauline +  and basal +
whitish +  and purplish +
0.8 cm8 mm <br />0.008 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
tuberculate +  and scabridulous +
fusiform +
0.6 cm6 mm <br />0.006 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
coriaceous +
wide +  and narrowing +
indistinguishable +
0 cm0 mm <br />0 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
inconspicuous +
scabridulous +  and smooth +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
concealed +  and prominent +
with straight +  and glabrous +
2 +  and 1 +
concealing +
0 +  and 1/2 +
12 cm120 mm <br />0.12 m <br /> (?) +
14 cm140 mm <br />0.14 m <br /> (30 cm300 mm <br />0.3 m <br />) +
dry +  and fleshy +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
not prolonged +
not disintegrating +
shorter or longer +
1 (?) +  and Anatomy (?) +
2 +  and 10 +
1 +  and 3 +
triangular +  and dome--shaped +
2 (?) +  and 3 (?) +
Aristida wrightii +
Aristida purpurea var. wrightii +
Aristida purpurea +
variety +
membranous +
0.9 cm9 mm <br />0.009 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
plant +  and cespitose +
aquatic +  and terrestrial +