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Howell's spineflower, Mendocino spineflower

brittle spine flower

Habit Plants spreading or decumbent to somewhat erect, 0.3–1 × 1–5 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 or nearly so;

petiole 1–4 cm;

blade spatulate to broadly obovate, 1–3 × 0.5–1.5(–1.8) cm, villous.

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 secondary branches suppressed, greenish to grayish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 1–5 cm × 5–15 mm, awns absent.

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 to grayish, broadly cylindric, not ventricose, 3–4 mm, with conspicuous, white, scarious margins between teeth and extending up awn, not corrugate, pubescent;

teeth spreading, equal, 0.5–1 mm, awns straight with longer ones 1–2 mm and anterior one mostly 2 mm, these alternating with shorter (0.5–1 mm) ones.

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

teeth divergent, 0.4–1.2 mm;

awns uncinate, 0.2–0.5 mm.

Flowers

exserted;

perianth bicolored with floral tube white and tepals white to rose, cylindric, (3–)3.5–4.5 mm, pubescent nearly throughout;

tepals connate 1/4 their length, dimorphic, oblong, truncate and erose to denticulate apically, those of outer lobes longer and wider than inner ones;

stamens 9, included;

filaments distinct, 3–4 mm, glabrous;

anthers pink to red, oblong, 0.6–0.8 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

light brown, globose-lenticular, 3–4.5 mm.

dark brown, lenticular, 3–4 mm.

2n

= (72, 74, 76, 78), 80, (82, 84, 86, 88, 90).

Chorizanthe howellii

Chorizanthe brevicornu

Phenology Flowering May–Jul.
Habitat Sandy places in coastal dunes and grassland communities
Elevation 0-20 m (0-100 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 howellii is an octoploid probably derived from an ancient hybrid event involving C. cuspidata var. villosa and perhaps C. valida. It is known only from a dune area north of Fort Bragg in Mendocino County, and is federally listed as endangered.

(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. 456. FNA vol. 5, p. 469.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Chorizanthe > subg. Amphietes > sect. Ptelosepala 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. 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. 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 Goodman: Ann. Missouri Bot. Gard. 21: 44, plate 3, fig. 1. (1934) Torrey: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 177. (1859)
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