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robust spineflower, Scotts Valley spineflower

diffuse spineflower

Habit Plants erect to spreading or decumbent, 0.5–3 × 0.1–6 dm, villous. Plants spreading, decumbent, prostrate, or rarely slightly erect, 0.3–1(–1.5) × 0.5–2(–10) dm, villous.
Leaves

basal or nearly so;

petiole 1–4(–7) cm;

blade oblanceolate, 1.5–5 × 0.2–0.7(–1) cm, villous.

basal;

petiole 0.2–1.8(–2) cm;

blade oblanceolate, 0.3–2 × 0.1–0.4 cm, villous.

Inflorescences

with secondary branches not suppressed except in terminal clusters of involucres, green to reddish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 1–5 cm × 2–5(–7) mm, awns absent.

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.

Involucres

1, greenish, cylindric, not ventricose, 2.5–4 mm, with white to pinkish, thin scarious margins restricted to basal portion of teeth, not corrugate, thinly pubescent abaxially;

teeth spreading, equal, 0.3–0.8(–1) mm;

awns uncinate with longer ones 0.7–1.3 mm and anterior one mostly 1–1.3 mm, these alternating with shorter (0.3–0.7 mm) ones.

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.

Flowers

slightly exserted;

perianth bicolored with floral tube white and tepals white to rose, cylindric, 2.5–4 mm, pubescent abaxially;

tepals connate 1/4 their length, monomorphic, oblanceolate to narrowly oblong, usually truncate to rounded and erose or denticulate apically, occasionally distinctly cuspidate;

stamens 9, included;

filaments distinct, 2–3.5 mm, glabrous;

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

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.

Achenes

light brown, globose-lenticular, 3.5–4 mm.

dark brown, globose-lenticular, 2–2.5 mm.

2n

= 38, 40, 42.

Chorizanthe robusta

Chorizanthe diffusa

Phenology Flowering Apr–Jul.
Habitat Sandy to gravelly flats and slopes, coastal scrub communities, pine-oak woodlands
Elevation 30-800 m (100-2600 ft)
Distribution
from USDA
wc Calif
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

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.)

Key
1. Margins of involucres white; plants spreading or decumbent; sandy to gravelly places; Alameda and San Mateo counties s in mountains and near coast to n Monterey County
var. robusta
1. Margins of involucres rose-pink; plants erect; annual grasslands near Scotts Valley, Santa Cruz Mountains, Santa Cruz County
var. hartwegii
Source FNA vol. 5, p. 455. FNA vol. 5, p. 452.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala 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. rigida, 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. 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
Subordinate taxa
C. robusta var. hartwegii, C. robusta var. robusta
Synonyms C. andersonii, C. diffusa var. nivea, C. nivea, C. pungens var. diffusa, C. pungens var. nivea
Name authority Parry: Proc. Davenport Acad. Nat. Sci. 5: 176. (1889) Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 26. (1856)
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