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robust spineflower, Scotts Valley spineflower

Photo is of parent taxon

robust spineflower, Scott Valley spineflower, Scott's Valley spineflower

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

basal or nearly so;

petiole 1–4(–7) cm;

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

blades 1.5–5 × 0.2–0.5(–0.7) cm.

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.

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.

2.5–3.5 mm, margins rose-pink.

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.

Achenes

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

Chorizanthe robusta

Chorizanthe robusta var. hartwegii

Phenology Flowering Apr–Jul.
Habitat Sandy outcrops, annual grassland communities
Elevation 200-300 m (700-1000 ft)
Distribution
from USDA
wc Calif
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Of conservation concern.

Variety hartwegii is known from a few populations in Scott Valley, Santa Cruz County. The epithet “hartwegii” was misapplied to Chorizanthe pungens var. hartwegiana until 1989; see B. Ertter (1996) for details. Scott Valley spineflower is federally listed as endangered.

(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. 456.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala > Chorizanthe robusta
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. robusta var. robusta
Subordinate taxa
C. robusta var. hartwegii, C. robusta var. robusta
Synonyms C. douglasii var. hartwegii, C. pungens var. hartwegii
Name authority Parry: Proc. Davenport Acad. Nat. Sci. 5: 176. (1889) (Bentham) Reveal & Rand. Morgan: Phytologia 67: 358. (1989)
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