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two lobed spineflower, two-lobe spineflower

two lobed spineflower, twolobe spineflower

Habit Plants erect or infrequently spreading, (0.5–)1–3(–4) × 1–3(–4) dm, pubescent.
Leaves

basal;

petiole 0.5–3 cm;

blade oblanceolate, 1–3(–5) × 0.4–1(–1.3) cm, thinly pubescent.

Inflorescences

with involucres in open clusters 2–4(–6) cm diam., greenish or reddish to purplish;

bracts 2–3 at proximal node, usually leaflike, often with whorl of sessile bracts ca. midstem, elliptic, 0.5–1.5 cm × 2–6 mm, gradually becoming lanceolate to elliptic, 0.2–2 cm × 1.5–8 mm, at distal nodes scalelike, linear and aciculate, acerose, awns straight, 1–3 mm.

Involucres

3–10 or more, grayish or reddish, urceolate and slightly ventricose basally, 4–6 mm, without scarious or membranous margins, slightly corrugate, strigose;

teeth erect to spreading, unequal, 1–2 mm;

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

Flowers

exserted;

perianth bicolored with floral tube white to yellow and tepals red, maroon, or dark purple, cylindric, (4.5–)5–6 mm, sparsely pubescent;

tepals connate 1/2 their length, dimorphic, obovate, those of outer whorl spreading, slightly longer than those of inner whorl, 2-lobed, emarginate, or subacute apically, those of inner whorl erect, obtuse, fimbriate apically;

stamens 9, exserted;

filaments distinct, 4–5 mm, glabrous;

anthers yellow to golden, oblong, 1.2–1.8 mm.

Outer tepals

deeply 2-lobed, occasionally erose apically.

Achenes

brown, globose-lenticular, 4–4.5 mm.

2n

= 40.

= (34, 36, 38), 40, (42, 44, 46).

Chorizanthe biloba var. biloba

Chorizanthe biloba

Phenology Flowering May–Aug.
Habitat Sandy, gravelly or clay soils, grassland communities, pine-oak woodlands
Elevation 200-700 m (700-2300 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Variety biloba is found from the eastern foothills of the Santa Lucia Mountains of Monterey and San Luis Obispo counties eastward to the western foothills of the Diablo, La Panza, and Temblor ranges, and in extreme western Fresno County.

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

Varieties 2 (2 in the flora).

Unlike the serpentine species Chorizanthe palmeri and C. ventricosa, C. biloba occurs on gravelly or clayey soils. Those species and C. obovata can be quickly differentiated by carefully examining the colors, shapes, and modifications of the tepals. Immature specimens can be difficult to place, but a combination of geographic location and edaphic features can often enable accurate identification of even fragmentary material.

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

Key
1. Outer tepals deeply 2-lobed, occasionally erose apically
var. biloba
1. Outer tepals emarginate or subcordate apically
var. immemora
Source FNA vol. 5, p. 458. FNA vol. 5, p. 458.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala > Chorizanthe biloba Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala
Sibling taxa
C. biloba var. immemora
C. angustifolia, 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. xanti
Subordinate taxa
C. biloba var. biloba, C. biloba var. immemora
Synonyms C. palmeri var. biloba
Name authority unknown Goodman: Ann. Missouri Bot. Gard. 21: 73. (1934)
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