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San Francisco spineflower

five-tooth spineflower, Watson's spineflower

Habit Plants decumbent to prostrate or ascending, 0.5–2(–2.5) × 0.5–10 dm, villous. Plants spreading to erect, 0.2–1(–1.5) × 0.2–1(–1.5) dm, densely canescent-strigose.
Leaves

basal;

petiole (0.5–)1–3 cm;

blade oblanceolate, (0.5–)1–5 × (0.3–)0.4–0.7(–1) 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, greenish to reddish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming narrowly elliptic to linear-lanceolate and aciculate at distal nodes, acerose, 0.5–5 cm × 2–7 mm, awns 0.5–1.2 mm.

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, greenish, cylindric, often ventricose basally, 1–3 mm, without scarious margins or if so then white to pink, thin, and restricted to basal portions of teeth, corrugate, villous abaxially;

teeth spreading, equal, 0.5–2 mm;

awns uncinate or straight with longer ones 2–3 mm and anterior one mostly 2.5–3 mm, these alternating with shorter 1–1.5(–1.7) 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

included to slightly exserted;

perianth bicolored with floral tube white and tepals white to rose, cylindric, 2–3 mm, pubescent abaxially;

tepals connate less than 1/4 their length, monomorphic, oblong, truncate to 3-lobed and distinctly cuspidate apically;

stamens 9, slightly exserted;

filaments distinct, 2–3 mm, glabrous;

anthers cream to rose, narrowly oblong, 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

light brown, globose-lenticular, 2–3 mm.

brown, lenticular, 2.5–3 mm.

Chorizanthe cuspidata

Chorizanthe watsonii

Phenology Flowering Apr–Aug.
Habitat Sandy to gravelly flats and slopes, mixed grassland, saltbush and sagebrush communities, pinyon-juniper woodlands
Elevation 300-2400 m (1000-7900 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; ID; NV; OR; UT; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

(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.)

Key
1. Involucral awns uncinate apically; San Francisco area
var. cuspidata
1. Involucral awns straight, rarely curved or with 1 awn uncinate; Marin and Sonoma counties
var. villosa
Source FNA vol. 5, p. 454. FNA vol. 5, p. 468.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Acanthogonum
Sibling taxa
C. angustifolia, C. biloba, C. blakleyi, C. brevicornu, C. breweri, C. clevelandii, C. corrugata, 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. 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. wheeleri, C. xanti
Subordinate taxa
C. cuspidata var. cuspidata, C. cuspidata var. villosa
Synonyms C. pungens var. cuspidata
Name authority S. Watson: Proc. Amer. Acad. Arts 17: 379. (1882) Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 199. (1870)
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