Chorizanthe diffusa |
Chorizanthe watsonii |
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diffuse spineflower |
five-tooth spineflower, Watson's spineflower |
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Habit | Plants spreading, decumbent, prostrate, or rarely slightly erect, 0.3–1(–1.5) × 0.5–2(–10) dm, villous. | Plants spreading to erect, 0.2–1(–1.5) × 0.2–1(–1.5) dm, densely canescent-strigose. |
Leaves | basal; petiole 0.2–1.8(–2) cm; blade oblanceolate, 0.3–2 × 0.1–0.4 cm, villous. |
basal or nearly so; petiole (0.5–)1–2.5(–3) cm; blade oblanceolate, (0.3–)0.5–1.5(–2) × 0.2–0.4(–0.5) cm, thinly floccose to sparsely tomentose. |
Inflorescences | rather dense with secondary branches suppressed, white to greenish; bracts 2, similar to leaf blades at proximal nodes only reduced, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 0.3–2 cm × 1–4 mm, awns absent. |
with involucres in small clusters 0.5–1 cm diam., greenish to reddish; bracts 2, with laminar ones oblanceolate, (0.5–)0.8–1.5(–2) cm × (1–)2–4 mm, those at distal nodes becoming sessile, reduced and scalelike, linear-lanceolate, acicular, awns slightly curved, 0.5–1 mm. |
Involucres | 1, mostly greenish, cylindric, not ventricose, 2–2.5 mm, with thin to broad and then conspicuous white or pinkish to purple, scarious margins extending nearly full length of awn, not corrugate, villous-hirsute; teeth spreading to divergent, equal, 0.5–1 mm, awns uncinate with longer ones 1–2 mm, anterior one mostly 2 mm, alternating with shorter (0.5–1 mm) ones. |
1, green, cylindric, 5-ribbed, 3–4.5 mm, finely corrugate, pubescent; teeth 5, erect, unequal, with leaflike, narrowly lanceolate, 2–6 mm anterior tooth, others linear, 1–2 mm; awn uncinate, 0.4–0.8(–1) mm. |
Flowers | exserted; perianth bicolored with floral tube lemon-yellow and tepals white, campanulate, 2.5–3 mm, glabrous; tepals connate ca. 1/3 their length, monomorphic, oblong, acute to obtuse and entire apically; stamens 3–9, slightly exserted; filaments distinct, 1.5–2 mm, glabrous; anthers yellow, oval, 0.3–0.4 mm. |
1, included to slightly exserted; perianth yellow, cylindric, 1.5–2.5 mm, thinly pubescent abaxially; tepals connate ca. 2/3 their length, monomorphic, oblong, acute, entire apically, mostly erect; stamens 3 or 9, slightly exserted; filaments distinct, 0.8–1 mm, glabrous; anthers yellow, ovate, 0.2–0.3 mm. |
Achenes | dark brown, globose-lenticular, 2–2.5 mm. |
brown, lenticular, 2.5–3 mm. |
2n | = 38, 40, 42. |
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Chorizanthe diffusa |
Chorizanthe watsonii |
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Phenology | Flowering Apr–Jul. | Flowering Apr–Aug. |
Habitat | Sandy to gravelly flats and slopes, coastal scrub communities, pine-oak woodlands | Sandy to gravelly flats and slopes, mixed grassland, saltbush and sagebrush communities, pinyon-juniper woodlands |
Elevation | 30-800 m (100-2600 ft) | 300-2400 m (1000-7900 ft) |
Distribution |
CA
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AZ; CA; ID; NV; OR; UT; WA
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Discussion | The involucral margins of Chorizanthe diffusa vary greatly. In some individuals, the white margins are barely visible. Plants with the margins of the involucre are predominantly white have been designated var. nivea. A full gradation between the extremes may be observed in most populations, although in coastal sands var. nivea is often the dominant expression. Diffuse spineflower occurs near the coast and in the Coast Ranges of central California. Chorizanthe diffusa has been shown to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary-organ culture model. This inhibitory activity is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis (see H. S. Chung et al. 1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Chorizanthe watsonii is widely distributed in the cold desert of the Great Basin and in the northern part of the warmer Mojave Desert. Plants in the northern part of the range (especially on the Palouse Prairie of south-eastern Washington) usually have three stamens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 452. | FNA vol. 5, p. 468. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. andersonii, C. diffusa var. nivea, C. nivea, C. pungens var. diffusa, C. pungens var. nivea | |
Name authority | Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 26. (1856) | Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 199. (1870) |
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