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diffuse spineflower

Douglas' spineflower, San Benito spineflower

Habit Plants spreading, decumbent, prostrate, or rarely slightly erect, 0.3–1(–1.5) × 0.5–2(–10) dm, villous. Plants erect, 1–4(–5) × 0.5–3 dm, villous.
Leaves

basal;

petiole 0.2–1.8(–2) cm;

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

basal;

petiole 1–3(–6) cm;

blade oblanceolate, 0.5–2(–4) × 0.1–0.4(–1) cm, villous.

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.

cymose, dichotomously branched throughout, white to greenish or reddish;

bracts usually 2, similar to proximal leaf blades, typically with whorl of 3–5 ca. midstem, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 0.5–2(–3) cm × 1–5(–10) mm, awns absent.

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.

congested in small leafy terminal clusters of 2–4 at nodes of dichotomies, greenish, cylindric, slightly ventricose basally, 3–5 mm, with conspicuous, purple, broad, membranous margins typically extending across sinuses, finely corrugated, hispid at least along ridges, otherwise sparsely pubescent;

teeth spreading, equal, (0.7–)1–1.5 mm, awns straight, 0.5–1 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.

exserted;

perianth white to rose, cylindric, 3.5–4(–4.5) mm, slightly pubescent abaxially;

tepals connate 2/3 their length, monomorphic, obovate, 2-lobed or denticulate apically, infrequently inner whorl entire;

stamens 9, slightly exserted;

filaments distinct, 3–4 mm, glabrous;

anthers pink to red, oblong, 0.5–0.6 mm.

Achenes

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

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

2n

= 38, 40, 42.

= 40.

Chorizanthe diffusa

Chorizanthe douglasii

Phenology Flowering Apr–Jul. Flowering Apr–Jul.
Habitat Sandy to gravelly flats and slopes, coastal scrub communities, pine-oak woodlands Sandy to gravelly flats and slopes, mixed grassland communities, oak and pine woodlands
Elevation 30-800 m (100-2600 ft) (200-)300-1600 m ((700-)1000-5200 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
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 douglasii is restricted to the Santa Lucia Mountains and to the San Gabilan and La Panza ranges of west-central California. The species is infrequent but can be locally common. A single collection made in the Santa Cruz Mountains (Rowntree s.n., 16 Jun 1929, CAS) may have been made in Santa Cruz County, but the location is uncertain and no other collection is known from that region.

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

Source FNA vol. 5, p. 452. 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. 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. 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
Synonyms C. andersonii, C. diffusa var. nivea, C. nivea, C. pungens var. diffusa, C. pungens var. nivea C. nortonii
Name authority Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 26. (1856) Bentham: Trans. Linn. Soc. London 17: 418. (1836)
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