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Orcutt spineflower, Orcutt's spineflower, San Diego spineflower

brittle spine flower

Habit Plants prostrate, 0.1–0.5 × 0.3–2(–2.5) dm, villous. Plants spreading to erect, 0.5–3(–5) × 0.5–3 dm, thinly pubescent, often with appressed hairs, infrequently somewhat strigose or glabrate.
Leaves

basal;

petiole 1–2 cm;

blade narrowly oblanceolate, 0.5–1.5 × 0.2–0.35(–0.5) cm, thinly pubescent.

basal;

petiole 0.5–2 cm;

blade oblanceolate to narrowly elliptic or spatulate, (1–)1.5–3(–4) × 0.1–1 cm, pubescent.

Inflorescences

with involucres in small clusters 0.5–1 cm diam., greenish;

bracts 2, sessile, unequal, 1 laminar and oblanceolate, 0.3–1 cm × 1–3 mm, awnless, this opposite linear, acicular, greatly reduced, 0.1–0.2 cm × 0.3–0.6 mm bract terminated by short, straight awn 0.6–1 mm.

green;

bracts 2, similar to proximal leaf blades only more reduced, 0.3–1(–1.5) cm × 1–2.5 mm, becoming sessile and scalelike at distal nodes, linear, acicular, awns 0.2–0.5 mm.

Involucres

1, greenish, campanulate, 3-ribbed, 0.8–2 mm, faintly corrugate, pubescent;

teeth 3, equal, 1.8–2 mm;

awns uncinate, 0.6–1 mm.

1, green, 3–5 mm, not corrugate, thinly strigose;

teeth divergent, 0.4–1.2 mm;

awns uncinate, 0.2–0.5 mm.

Flowers

1, included to slightly exserted;

perianth yellow, cylindric, 1.5–1.8 mm, densely pubescent abaxially;

tepals connate ca. 1/2 their length, monomorphic, narrowly oblanceolate, obtuse to truncate, entire apically, slightly spreading;

stamens 9, slightly exserted;

filaments distinct, 0.5–0.8 mm, glabrous;

anthers reddish, ovate, 0.2–0.3 mm.

included;

perianth greenish white to white or pale yellowish white, cylindric, 2–4 mm;

tepals connate 3/4 their length, monomorphic, linear to narrowly oblanceolate, acute, entire apically;

stamens slightly exserted;

filaments distinct, 2–3.5 mm, glabrous;

anthers white to pale yellow, ovate, 0.3–0.4 mm.

Achenes

dark brown, lenticular, 2–2.2 mm.

dark brown, lenticular, 3–4 mm.

2n

= (76, 78), 80, (84).

Chorizanthe orcuttiana

Chorizanthe brevicornu

Phenology Flowering Mar–May.
Habitat Sandy soil, mesas and hills near coast, coastal scrub communities
Elevation 60-200 m (200-700 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
AZ; CA; ID; NV; OR; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Chorizanthe orcuttiana is known from a few populations on coastal mesas and hills near San Diego, San Diego County. It is federally listed as endangered. The species is an octoploid that may well have resulted from an ancient hybridization and doubling of chromosomes involving C. procumbens and C. polygonoides var. longispina. The Orcutt spineflower grows in soft, white sand; C. procumbens and C. polygonoides var. longispina are restricted to gravelly sites.

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

Varieties 2 (2 in the flora).

Chorizanthe brevicornu has stems and branches that easily disarticulate at the nodes. Dried specimens often are reduced to a mere jumble without careful handling. The vegetative fragments will not regenerate new plants, but the involucres (each with a single flower bearing a single achene) easily disarticulate from the parent plant, and with the aid of the awns on the teeth of the involucre, may be readily distributed.

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

Key
1. Leaf blades oblanceolate to narrowly elliptic, 0.1-0.3(-0.5) cm wide; involucres prominently ribbed at maturity; Mojave and Sonoran deserts
var. brevicornu
1. Leaf blades broadly oblanceolate to broadly spatulate, 0.5-1 cm wide; involucres obscurely ribbed at maturity; Great Basin Desert and Snake River Plains
var. spathulata
Source FNA vol. 5, p. 467. FNA vol. 5, p. 469.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Acanthogonum Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Fragile
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. 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. biloba, C. blakleyi, 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. brevicornu var. brevicornu, C. brevicornu var. spathulata
Name authority Parry: Proc. Davenport Acad. Nat. Sci. 4: 54. (1884) Torrey: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 177. (1859)
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