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California three-awn, Mojave three-awn

churchmouse three-awn

Habit Plants perennial; sometimes flowering the first year. Plants annual.
Culms

10-40 cm, highly branched above the base in age;

internodes glabrous or pubescent, sometimes nearly lanose.

15-60 cm, erect or geniculate at the base, branching at most of the nodes.

Leaves

cauline;

sheaths shorter than the internodes, glabrous or puberulent;

collars glabrous or pubescent at the sides;

ligules 0.5-1 mm;

blades usually less than 6 cm long, 0.5-1 mm wide, pale green, involute, glabrous or puberulent abaxially.

cauline;

sheaths usually shorter than the internodes, glabrous or sparsely pilose;

collars glabrous;

ligules less than 0.5 mm;

blades 3-10 cm long, 1-2 mm wide, flat to folded basally, involute distally, scabridulous on both surfaces, occasionally sparsely pilose adaxially, light green.

Inflorescences

paniculate or racemose, 5-10 cm long, 1-2 cm wide, with few spikelets;

rachis nodes glabrous or with straight hairs;

primary branches 1-2 cm, appressed, without axillary pulvini.

paniculate or racemose, 2-11 cm long, to 1 cm wide;

nodes glabrous or strigillose;

primary branches 1-2 cm, appressed, without axillary pulvini, with 1-2 spikelets.

Spikelets

appressed.

partly overlapping, often in pairs, 1 spikelet subsessile, the other pedicellate.

Glumes

unequal, 1-2-veined;

lower glumes 4-10 mm;

upper glumes 7-15 mm;

calluses about 1 mm;

lemmas 5-7 mm, purple or mottled, junction of the lemma and awns evident;

awns twisted together basally into a 4-26 mm column, free portions 12-50 mm, those of the central and lateral awns similar in length, curved to arcuate basally, straight and divergent distally, disarticulating at the base of the column at maturity;

anthers 3, about 2 mm long.

1-veined, light gray to dark purplish or brownish;

lower glumes 3-8(10) mm, from 1/2 as long as the upper glumes to nearly equaling them;

upper glumes 4-13 mm;

calluses 0.3-0.5 mm;

lemmas 3-11 mm, light gray to purplish, frequently mottled, midveins scabrous, elsewhere glabrous, scabridulous, or sparsely appressed-puberulent, junction with the awns not evident;

central awns 3-8 mm, coiled at the base, spreading distally;

lateral awns 1-4 mm, straight, erect;

anthers 3 and 2-3 mm, or 1 and about 0.25 mm.

Caryopses

light brown.

2n

= 22.

= unknown.

Aristida californica

Aristida dichotoma

Distribution
from FNA
AZ; CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

The range of both varieties of Aristida californica extends from the southwestern United States into northwestern Mexico.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Aristida dichotoma grows in sandy fields and clearings, disturbed sites and sterile ground, pine woods, and on granitic outcrops of the United States and southern Ontario. The two varieties have similar ecological preferences and extensive overlap in their ranges, but var. curtissii is somewhat more western in its distribution.

Aristida dichotoma is similar to A. basiramea, differing in its shorter lateral awns. Further study may show that the two should be treated as conspecific varieties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Cauline internodes puberulent to nearly lanose
var. californica
1. Cauline internodes glabrous
var. glabrata
1. Glumes unequal; lemmas smooth or scabridulous, 6-11 mm long
var. curtissii
1. Glumes equal or subequal; lemmas sparsely appressed-pubescent, 3-8 mm long
var. dichotoma
Source FNA vol. 25, p. 319. FNA vol. 25, p. 328.
Parent taxa Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida
Sibling taxa
A. adscensionis, A. arizonica, A. basiramea, A. condensata, A. desmantha, A. dichotoma, A. divaricata, A. floridana, A. gypsophila, A. gyrans, A. havardii, A. lanosa, A. longespica, A. mohrii, A. oligantha, A. palustris, A. pansa, A. patula, A. purpurascens, A. purpurea, A. ramosissima, A. rhizomophora, A. schiedeana, A. simpliciflora, A. spiciformis, A. stricta, A. ternipes, A. tuberculosa
A. adscensionis, A. arizonica, A. basiramea, A. californica, A. condensata, A. desmantha, A. divaricata, A. floridana, A. gypsophila, A. gyrans, A. havardii, A. lanosa, A. longespica, A. mohrii, A. oligantha, A. palustris, A. pansa, A. patula, A. purpurascens, A. purpurea, A. ramosissima, A. rhizomophora, A. schiedeana, A. simpliciflora, A. spiciformis, A. stricta, A. ternipes, A. tuberculosa
Subordinate taxa
A. californica var. californica, A. californica var. glabrata
A. dichotoma var. curtissii, A. dichotoma var. dichotoma
Name authority Thurb. Michx.
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