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devil's spineflower, rigid spineflower, rigid spiny-herb, spiny-herb

Santa Barbara spineflower, Wheeler's spineflower

Habit Plants erect, 0.2–0.8(–1.5) × 0.1–0.7(–1) dm, pubescent. Plants erect to spreading, 0.5–2(–2.5) × 1–2 dm, thinly pubescent.
Leaves

basal and cauline;

petiole 0.5–3(–4) cm;

basal blade broadly elliptic to obovate, 0.5–2.5 × (0.3–)0.5–2 cm, thinly pubescent adaxially, more densely so to tomentose abaxially;

proximal cauline leaf soon deciduous, 1, blade similar to basal leaf blades only 1–2(–2.5) × 0.5–1.5 cm, mucronate to awn-tipped, awn mostly 2–4 mm;

distal cauline leaf blade persistent, 1 per node, sessile, blade linear to linear-lanceolate, 0.1–1.5 × 0.05–0.15 cm, becoming hard and thornlike with age.

basal;

petiole 0.5–3 cm;

blade elliptic to oblong, 0.5–2 × 0.2–0.6 cm, thinly pubescent adaxially, tomentose abaxially.

Inflorescences

with involucres in dense clusters in axils of bracts, these on short shoots and each subtended by cauline leaves;

bracts 2, subopposite to opposite, linear, 0.5–1(–1.2) cm × 1–2 mm, awns straight, 2–4 mm.

mostly flat-topped, openly branched, greenish to reddish;

bracts persistent, 2, usually leaflike at proximal nodes and similar to leaf blades, short-petiolate, oblong, 0.5–1.2 cm × 2–4 mm, sessile, reduced and scalelike at distal nodes, linear, acicular, often acerose, 0.1–0.5 cm × 0.5–1 mm, awns straight, 0.5–1 mm.

Involucres

1, greenish, urceolate, 3-ribbed, 2–3 mm, corrugate, pubescent, rarely villous near base in some;

teeth 3, unequal, with thickened anterior tooth toward base, 5–10 mm, sometimes expanding and becoming lanceolate to narrowly elliptic, others 0.5–1.2 mm;

awns straight.

in dense terminal clusters with 1 at node of dichotomies, reddish, cylindric, not ventricose, 2–2.5 mm, corrugate, without scarious or membranous margins, thinly pubescent with stoutish, recurved hairs;

teeth spreading, unequal, 0.3–0.8(–1) mm, with 3 longer ones more erect than 3 shorter and less-prominent ones;

awns uncinate, 0.3–0.5 mm.

Flowers

1–2, included to slightly exserted;

perianth yellow, cylindric, 1.5–1.8 mm, densely pubescent abaxially;

tepals connate ca. 2/3 their length, monomorphic, oblong, rounded, entire apically;

stamens 9, slightly exserted;

filaments distinct, 0.5–1 mm, glabrous;

anthers yellowish, ovate, 0.2–0.3 mm.

exserted;

perianth white or rose or red with white lobes, cylindric, 2.5–3 mm, glabrous except for few scattered hairs ca. midlength along midrib abaxially;

tepals connate 1/2 their length, monomorphic to slightly dimorphic, oblong, rounded apically, those of outer whorl usually slightly broader and longer than those of inner whorl;

stamens 6, included;

filaments distinct, 1.5–2 mm, glabrous;

anthers pink to red, oblong, 0.3–0.4 mm.

Achenes

brown, 3-gonous, (1.5–)1.8–2.2 mm.

brown, lenticular, 2.5–3 mm.

2n

= 38, 40.

Chorizanthe rigida

Chorizanthe wheeleri

Phenology Flowering Feb–Jun. Flowering Apr–Jun.
Habitat Sandy to gravelly or rocky flats and slopes, desert scrub Gravelly to rocky slopes, coastal scrub communities
Elevation -60-1900 m. (-200-6200 ft.) 0-400(-600) m (0-1300(-2000) ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Anyone with the misfortune to step bare-footed on Chorizanthe rigida after the plant has dried instantly appreciates its common name. The species is widespread on the Mojave and Sonoran deserts but only occasionally is it locally abundant or weedy. It is found also along the Lahontan Trough in western Nevada, a well-known biogeographic extension route north of the Mojave Desert (J. L. Reveal 1980). The exceedingly compact and dense inflorescences with suppressed secondary branches result in a series of leaves and bracts that subtend a closely arranged series of bracteated and involucrated flowers.

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

Chorizanthe wheeleri is a rare insular endemic known only from Santa Cruz and Santa Rosa islands.

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

Source FNA vol. 5, p. 467. FNA vol. 5, p. 464.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Acanthogonum Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala
Sibling taxa
C. angustifolia, C. biloba, C. blakleyi, C. brevicornu, C. breweri, C. clevelandii, C. corrugata, C. cuspidata, C. diffusa, C. douglasii, C. fimbriata, C. howellii, C. leptotheca, C. membranacea, C. obovata, C. orcuttiana, C. palmeri, C. parryi, C. polygonoides, C. procumbens, C. pungens, C. rectispina, C. robusta, C. spinosa, C. staticoides, C. stellulata, C. uniaristata, C. valida, C. ventricosa, C. watsonii, C. wheeleri, C. xanti
C. angustifolia, C. biloba, C. blakleyi, C. brevicornu, C. breweri, C. clevelandii, C. corrugata, C. cuspidata, C. diffusa, C. douglasii, C. fimbriata, C. howellii, C. leptotheca, C. membranacea, C. obovata, C. orcuttiana, C. palmeri, C. parryi, C. polygonoides, C. procumbens, C. pungens, C. rectispina, C. rigida, C. robusta, C. spinosa, C. staticoides, C. stellulata, C. uniaristata, C. valida, C. ventricosa, C. watsonii, C. xanti
Synonyms Acanthogonum rigidum C. insularis
Name authority (Torrey) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 198. (1870) S. Watson: Proc. Amer. Acad. Arts 12: 272. (1877)
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