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robust spineflower, Scotts Valley spineflower

Santa Barbara spineflower, Wheeler's spineflower

Habit Plants erect to spreading or decumbent, 0.5–3 × 0.1–6 dm, villous. Plants erect to spreading, 0.5–2(–2.5) × 1–2 dm, thinly pubescent.
Leaves

basal or nearly so;

petiole 1–4(–7) cm;

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

basal;

petiole 0.5–3 cm;

blade elliptic to oblong, 0.5–2 × 0.2–0.6 cm, thinly pubescent adaxially, tomentose abaxially.

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.

mostly flat-topped, openly branched, greenish to reddish;

bracts persistent, 2, usually leaflike at proximal nodes and similar to leaf blades, short-petiolate, oblong, 0.5–1.2 cm × 2–4 mm, sessile, reduced and scalelike at distal nodes, linear, acicular, often acerose, 0.1–0.5 cm × 0.5–1 mm, awns straight, 0.5–1 mm.

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.

in dense terminal clusters with 1 at node of dichotomies, reddish, cylindric, not ventricose, 2–2.5 mm, corrugate, without scarious or membranous margins, thinly pubescent with stoutish, recurved hairs;

teeth spreading, unequal, 0.3–0.8(–1) mm, with 3 longer ones more erect than 3 shorter and less-prominent ones;

awns uncinate, 0.3–0.5 mm.

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 white or rose or red with white lobes, cylindric, 2.5–3 mm, glabrous except for few scattered hairs ca. midlength along midrib abaxially;

tepals connate 1/2 their length, monomorphic to slightly dimorphic, oblong, rounded apically, those of outer whorl usually slightly broader and longer than those of inner whorl;

stamens 6, included;

filaments distinct, 1.5–2 mm, glabrous;

anthers pink to red, oblong, 0.3–0.4 mm.

Achenes

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

brown, lenticular, 2.5–3 mm.

Chorizanthe robusta

Chorizanthe wheeleri

Phenology Flowering Apr–Jun.
Habitat Gravelly to rocky slopes, coastal scrub communities
Elevation 0-400(-600) m (0-1300(-2000) 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.)

Chorizanthe wheeleri is a rare insular endemic known only from Santa Cruz and Santa Rosa islands.

(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. 464.
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. 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. xanti
Subordinate taxa
C. robusta var. hartwegii, C. robusta var. robusta
Synonyms C. insularis
Name authority Parry: Proc. Davenport Acad. Nat. Sci. 5: 176. (1889) S. Watson: Proc. Amer. Acad. Arts 12: 272. (1877)
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