Chorizanthe rigida |
Chorizanthe sect. Acanthogonum |
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devil's spineflower, rigid spineflower, rigid spiny-herb, spiny-herb |
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Habit | Plants erect, 0.2–0.8(–1.5) × 0.1–0.7(–1) dm, pubescent. | Plants prostrate to spreading or erect. |
Stems | not disarticulating at each node. |
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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. |
blades oblanceolate to elliptic or round. |
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. |
bracts awned or awnless. |
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. |
cylindric, campanulate, or urceolate, not ventricose basally, 3-angled, 3-ribbed, 3-, 5-, or occasionally 6-toothed, without membranous or scarious margins; awns equal, sometimes anterior one longest. |
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. |
1(–2); perianth white to rose or yellow, thinly to densely pubescent; stamens 3, 6, or 9; filaments adnate faucially at or near top of floral tube. |
Achenes | brown, 3-gonous, (1.5–)1.8–2.2 mm. |
brown to black, lenticular or 3-gonous. |
2n | = 38, 40. |
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Chorizanthe rigida |
Chorizanthe sect. Acanthogonum |
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Phenology | Flowering Feb–Jun. | |
Habitat | Sandy to gravelly or rocky flats and slopes, desert scrub | |
Elevation | -60-1900 m. (-200-6200 ft.) | |
Distribution |
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
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w United States; nw Mexico |
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.) |
Species 5 (5 in the flora). G. J. Goodman (1934) assigned Chorizanthe polygonoides to Acanthogonum, which previously included C. rigida and C. corrugata (see below). J. L. Reveal and C. B. Hardham (1989b) considered that taxon to represent a section within Chorizanthe, expanded it further to include both C. orcuttiana and C. watsonii, and divided it into five subsections. Section Acanthogonum differs from sect. Ptelosepala by having involucral tubes that are not both 6-ribbed and 6-toothed at the same time. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 467. | FNA vol. 5, p. 466. |
Parent taxa | ||
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Acanthogonum rigidum | section Acanthogonum, C. section Chorizanthella |
Name authority | (Torrey) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 198. (1870) | (Torrey) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 197. (1870) |
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