Plants perennial; cespitose, neither rhizomatous nor stoloniferous. Culms
40-100 cm, erect, sometimes geniculate, not rooting, at the lower nodes. Basal
sheaths villous; upper sheaths glabrous, densely villous or densely
tomentose, or sparsely to densely hairy, with papillose-based hairs; ligules (1)1.5-6
mm, entire or lacerate, not ciliate; blades 2-12(18) cm long, 2-5(7)
mm wide, glabrous or the adaxial surfaces sparsely to densely villous or tomentose.
Panicles with 4-10 spikelike primary branches on 5-10 cm rachises, rarely
with secondary branches; primary branches 3-6 cm, appressed to ascending,
axes not wing-margined; internodes 2-5.5 mm (mid branch), with spikelets
in unequally pedicellate pairs;secondary branches rarely present; pedicels
not adnate to the branch axes; shorter pedicels 0.1-0.3 mm; longer
pedicels 1-2 mm; terminal pedicels of branches 1.7-6(7) mm. Spikelets
homomorphic, (3.7)4-7.5 mm (including pubescence), 3-5.4 mm (excluding pubescence).
Lower glumes 0.4-0.6 mm; upper glumes 2.5-5.1 mm (excluding pubescence),
narrower than the upper florets, 3-veined, densely villous, hairs 1.5-5 mm,
silvery-white to purple, widely divergent at maturity; lower lemmas 2.7-5
mm (excluding pubescence), pubescence exceeding the upper florets by 2.2-4 mm,
7-veined, veins unequally spaced, only the 3 or 5 central veins visible, margins
and outer lateral veins densely pubescent, hairs 1.5-5 mm, silvery-white to
purple, widely divergent at maturity, intercostal regions glabrous, apices attenuate
(acuminate); upper lemmas 2.5-3.4 mm, ovate-lanceolate, brown to dark
brown, acuminate. Caryopses 1.3-2 mm. 2n = 36, 54, 70, 72.
Digitaria californica grows on plains and open ground from Arizona, southern
Colorado, and Oklahoma through Mexico and Central America to South America.
The name reflects the fact that the first collection was made in Baja California,
Mexico. Plants in the Flora region belong to D. californica (Benth.)
Henrard var. californica. They differ from those of D. californica
var. villosissima Henrard in having densely villous, rather than densely
FNA 2003, Gould 1980
Common Name: Arizona cottontop Duration: Perennial Nativity: Native Lifeform: Graminoid General: Caespitose perennial grass, 40-100 cm tall, with erect, glabrous stems from a swollen, knotty base. Vegetative: Sheaths open, longer than internodes, the lower sheaths pubescent; blades flat or folded, glaucous, bluish-green, 3-4 mm wide, 8-12 cm long, pustulate hairs on upper side near ligule, hairs sometimes sparse; ligule membranous, obtuse, erose, 2 mm long. Inflorescence: Contracted panicle 8-20 cm long with few branches, these erect, appressed; spikelets 3-4 mm long, excluding hairs, second glume narrow densely villous with soft, white-silky hairs tinged with purple, 2-4 mm long; sterile lemma broad, three-nerved, villous on margins but glabrous between the nerves; caryopsis ovate-lanceolate, narrowing to short awn. Ecology: Open, well-drained soils, often on steep, rocky slopes; 1,000-6000 ft (305-1829 m); flowers August-October. Distribution: s CA, west through all of AZ, NM, s CO, TX and s OK; south through Mexico to south America. Notes: Distinguished by being an erect, caespitose perennial with a terminal inflorescence of long branches with rows of sessile, single-flowered, flattened spikelets with long, soft hairs giving the inflorescence a cottony, soft white or silver appearance; the spikelets are quickly deciduous and fall from the plant quickly after ripening. Ethnobotany: Unknown, but other species in the genus have uses. Etymology: Digitaria is from Latin digitus, a finger and californica is for California. Synonyms: Trichachne californica Editor: SBuckley 2010, FSCoburn 2014, AHazelton 2015