Chorizanthe spinosa |
Chorizanthe rigida |
|
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Mojave spineflower |
devil's spineflower, rigid spineflower, rigid spiny-herb, spiny-herb |
|
Habit | Plants spreading to prostrate, 0.3–0.8(–1) × 0.5–8 dm. | Plants erect, 0.2–0.8(–1.5) × 0.1–0.7(–1) dm, pubescent. |
Leaves | basal; petiole 0.5–2 cm; blade (0.3–)0.5–1.5(–2) × (3–)5–10(–12) mm, thinly pubescent adaxially, more densely so to tomentose abaxially. |
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. |
Inflorescences | greenish to reddish, mostly flat-topped and open to dense; bracts 3, whorled, short-petiolate, linear-lanceolate to lanceolate, acerose, 0.5–1.5 cm × 3–8(–10) mm, awns straight, 1–3.5 mm. |
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. |
Involucres | usually congested in small terminal clusters of 1–3 at node of dichotomies, (4–)5-ribbed, weakly 3-angled, 2–2.5 mm, not corrugate, densely canescent; teeth (4–)5, essentially erect with longer, prominent, and thickened anterior one 2–4 mm, with straight awn 1–2.5 mm, remaining teeth smaller, 0.5–1 mm, with straight awns 0.3–0.8 mm. |
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. |
Flowers | 1, exserted; perianth, cylindric, 2.5–3.5 mm; tepals connate 1/2–2/3 their length, dimorphic, entire, those of outer whorl spreading, broadly obovate and rounded apically, those of inner whorl erect, narrowly oblanceolate, 1/2 length of outer ones, acute apically; stamens slightly exserted; filaments 2.5–3 mm, glabrous; anthers yellowish, oblong, 0.5–0.7 mm. |
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. |
Achenes | 2.5–3 mm. |
brown, 3-gonous, (1.5–)1.8–2.2 mm. |
2n | = (40), 44, (46). |
= 38, 40. |
Chorizanthe spinosa |
Chorizanthe rigida |
|
Phenology | Flowering Apr–Jul. | Flowering Feb–Jun. |
Habitat | Sandy to gravelly flats and slopes, saltbush communities | Sandy to gravelly or rocky flats and slopes, desert scrub |
Elevation | 600-1300 m (2000-4300 ft) | -60-1900 m. (-200-6200 ft.) |
Distribution |
CA
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AZ; CA; NV; UT; Mexico (Baja California, Sonora)
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Discussion | G. J. Goodman (1934) referred Chorizanthe spinosa to Eriogonella, but C. spinosa and C. membranacea, the type of Eriogonella, are well isolated from one another, and both are well removed from the remainder of the annual spineflowers. The Mojave spineflower is local and uncommon from southeastern Kern and southern Inyo counties, south into adjacent northeastern Los Angeles and northwestern San Bernardino counties to Antelope and Lucerne valleys. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 5, p. 449. | FNA vol. 5, p. 467. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Eriogonella spinosa | Acanthogonum rigidum |
Name authority | S. Watson: in W. H. Brewer et al., Bot. California 2: 481. (1880) | (Torrey) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 198. (1870) |
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