The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

San Francisco spineflower

two lobed spineflower, twolobe spineflower

Habit Plants decumbent to prostrate or ascending, 0.5–2(–2.5) × 0.5–10 dm, villous. Plants erect or infrequently spreading, (0.5–)1–3(–4) × 1–3(–4) dm, pubescent.
Leaves

basal;

petiole (0.5–)1–3 cm;

blade oblanceolate, (0.5–)1–5 × (0.3–)0.4–0.7(–1) cm, villous.

basal;

petiole 0.5–3 cm;

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

Inflorescences

rather dense with secondary branches suppressed, greenish to reddish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming narrowly elliptic to linear-lanceolate and aciculate at distal nodes, acerose, 0.5–5 cm × 2–7 mm, awns 0.5–1.2 mm.

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

1, greenish, cylindric, often ventricose basally, 1–3 mm, without scarious margins or if so then white to pink, thin, and restricted to basal portions of teeth, corrugate, villous abaxially;

teeth spreading, equal, 0.5–2 mm;

awns uncinate or straight with longer ones 2–3 mm and anterior one mostly 2.5–3 mm, these alternating with shorter 1–1.5(–1.7) mm ones.

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

included to slightly exserted;

perianth bicolored with floral tube white and tepals white to rose, cylindric, 2–3 mm, pubescent abaxially;

tepals connate less than 1/4 their length, monomorphic, oblong, truncate to 3-lobed and distinctly cuspidate apically;

stamens 9, slightly exserted;

filaments distinct, 2–3 mm, glabrous;

anthers cream to rose, narrowly oblong, 0.3–0.4 mm.

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.

Achenes

light brown, globose-lenticular, 2–3 mm.

brown, globose-lenticular, 4–4.5 mm.

2n

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

Chorizanthe cuspidata

Chorizanthe biloba

Distribution
from FNA
CA
[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.)

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. Involucral awns uncinate apically; San Francisco area
var. cuspidata
1. Involucral awns straight, rarely curved or with 1 awn uncinate; Marin and Sonoma counties
var. villosa
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. 454. 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. 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
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. cuspidata var. cuspidata, C. cuspidata var. villosa
C. biloba var. biloba, C. biloba var. immemora
Synonyms C. pungens var. cuspidata C. palmeri var. biloba
Name authority S. Watson: Proc. Amer. Acad. Arts 17: 379. (1882) Goodman: Ann. Missouri Bot. Gard. 21: 73. (1934)
Web links