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riverside spineflower, Xantus' spineflower

potbellied spineflower, Priest Valley spineflower

Habit Plants erect to infrequently spreading, (0.3–)0.5–2.5(–3) × 0.5–3(–5) dm, thinly pubescent. Plants spreading and diffuse, (0.5–)1–5 × 1–5(–7) dm, pubescent.
Leaves

basal or nearly so;

petiole 1–2(–3) cm;

blade oblong or oblong-ovate to ovate, 0.3–1(–1.5) × 0.3–0.8(–1) cm, thinly pubescent adaxially, densely tomentose abaxially.

basal;

petiole 0.3–1(–1.5) cm;

blade oblanceolate, (0.5–)1–3(–4) × (0.2–)0.4–1(–1.2) cm, thinly pubescent.

Inflorescences

mostly flat-topped and openly branched, usually reddish;

bracts persistent, 2, usually leaflike at proximal nodes and similar to proximal leaf blades only more reduced, short-petiolate, oblong-ovate to ovate, 0.3–0.8 cm × 2–6 mm, becoming sessile, reduced and scalelike at distal nodes, linear, acicular, often acerose, 0.1–0.4 cm × 0.5–1 mm, awns straight, 0.5–1 mm.

with involucres in open clusters 2–6 cm diam., greenish or reddish;

bracts 2–3 at proximal node, usually leaflike, often with whorl of sessile bracts about midstem, oblanceolate to elliptic, 0.5–1.5 cm × 1–4 mm, gradually becoming reduced, linear-lanceolate, 0.4–1.2(–1.5) cm × 1.5–5 mm, at distal nodes scalelike, linear and aciculate, acerose, awns straight, 1–3 mm.

Involucres

in open clusters with 1 at node of dichotomies, reddish, cylindric, not ventricose, 3–4.5 mm, not corrugate, without scarious or membranous margins, thinly to densely pubescent;

teeth spreading, unequal, 0.7–1.5 mm, 3 longer ones more erect than 3 shorter and less-prominent ones;

awns uncinate, 0.5–1 mm.

3–10+, greenish or reddish, urceolate, strongly ventricose basally, 4–4.5 mm, without scarious or membranous margins, corrugate, thinly pubescent;

teeth spreading, unequal, 1–3 mm;

awns straight or uncinate with longer anterior one straight, mostly 2 mm, others uncinate, 0.5–1 mm.

Flowers

long-exserted;

perianth rose to red, infrequently with white lobes, cylindric, 4.5–6 mm, pubescent;

tepals connate ca. 2/3 their length, monomorphic to slightly dimorphic, narrowly oblanceolate, rounded apically, those of outer whorl occasionally slightly broader and longer than those of inner whorl;

stamens 9, mostly included;

filaments distinct, 4–6 mm, glabrous;

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

exserted;

perianth bicolored with floral tube white to greenish yellow and tepals red to maroon, cylindric, 4–4.5 mm, sparsely pubescent;

tepals connate 1/2 their length, dimorphic, oblong, those of outer whorl spreading and recurved, slightly longer than those of inner whorl, broadly obcordate, slightly erose or at least wavy and rounded apically, those of inner whorl erect, narrower, fimbriate and truncate or somewhat 2-lobed apically, erect;

stamens 9, exserted;

filaments distinct, 3.5–4 mm, glabrous;

anthers pink to red or maroon, oblong, 1–1.3 mm.

Achenes

brown, lenticular, 4–4.5 mm.

brown, globose-lenticular, 3–3.5 mm.

2n

= 40, 42, 44.

Chorizanthe xanti

Chorizanthe ventricosa

Phenology Flowering May–Sep.
Habitat Serpentine outcrops, mixed grassland communities, oak-pine woodlands
Elevation 500-1000 m (1600-3300 ft)
Distribution
from FNA
CA
[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.)

Chorizanthe ventricosa is restricted to isolated outcrops of serpentine in the coastal mountain ranges of southeastern Monterey County and southern San Benito County south in western Fresno County to the Parkfield Grade area and in Cottonwood Pass of San Luis Obispo County.

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

Key
1. Involucres thinly pubescent
var. xanti
1. Involucres densely white-pubescent
var. leucotheca
Source FNA vol. 5, p. 463. FNA vol. 5, p. 458.
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. robusta, C. spinosa, C. staticoides, C. stellulata, C. uniaristata, C. valida, C. ventricosa, C. watsonii, C. wheeleri
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. watsonii, C. wheeleri, C. xanti
Subordinate taxa
C. xanti var. leucotheca, C. xanti var. xanti
Synonyms C. palmeri var. ventricosa
Name authority S. Watson: Proc. Amer. Acad. Arts 12: 272. (1877) Goodman: Leafl. W. Bot. 2: 193, figs. 1, 2. (1939)
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