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

Sonoma spineflower

Habit Plants erect, 0.2–0.8(–1.5) × 0.1–0.7(–1) dm, pubescent. Plants erect to spreading, 1–3 × 1–6 dm, villous.
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 or nearly so;

petiole 1–3 cm;

blade broadly oblanceolate, 1–2.5(–5) × 0.4–0.8(–1.2) cm, usually villous.

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.

with secondary branches suppressed, grayish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 1–3 cm × 6–10 mm, awns absent.

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.

1, grayish, cylindric, not ventricose,3–4(–4.5) mm, with white, scarious margins between teeth, finely corrugate, thinly pubescent;

teeth erect, equal, 0.3–0.7(–1) mm;

awns straight, with longer ones 0.7–1.3 mm and anterior one mostly 1.3 mm, these alternating with shorter, 0.5–1(–1.2) mm ones.

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 bicolored with floral tube white and tepals white to lavender or rose, cylindric, (4–)5–6 mm, pubescent on proximal 1/2;

tepals connate 1/4 their length, dimorphic, oblong, truncate and erose to denticulate, sometimes individual lobes entire, 2-lobed or even cuspidate apically, those of outer lobes longer and wider than inner ones;

stamens 9, included;

filaments distinct, 2–4.5 mm, glabrous;

anthers pink to red or maroon, oblong, 0.6–0.8(–1) mm.

Achenes

brown, 3-gonous, (1.5–)1.8–2.2 mm.

light brown, lenticular-globose, 3–4.5 mm.

2n

= 38, 40.

Chorizanthe rigida

Chorizanthe valida

Phenology Flowering Feb–Jun. Flowering Jun–Aug.
Habitat Sandy to gravelly or rocky flats and slopes, desert scrub Sandy places, coastal grassland communities
Elevation -60-1900 m. (-200-6200 ft.) 10-100 m (0-300 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.)

Of conservation concern.

Chorizanthe valida may be distinguished by the highly colored involucre. The teeth and bases of awns are bright red. The awns then quickly transform to a bright ivory and this color dominates nearly the length of each awn. In the more inland populations (now extirpated), the awns observed in the old collections appear to be a straw color. It is not known if this is an artifact of age or potentially significant. Sonoma spineflower is now known only from grassy fields south of Abbott’s Lagoon in the Point Reyes area of Marin County (L. Davis and R. J. Sherman 1990, 1992). The last collection from Sonoma County was made at Sebastopol in 1907. The type, collected in 1841, apparently was gathered near Fort Ross, also in Sonoma County. This species is federally listed as endangered.

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

Source FNA vol. 5, p. 467. FNA vol. 5, p. 456.
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. ventricosa, C. watsonii, C. wheeleri, C. xanti
Synonyms Acanthogonum rigidum
Name authority (Torrey) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 198. (1870) S. Watson: Proc. Amer. Acad. Arts 12: 271. (1877)
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