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robust spineflower, Scotts Valley spineflower

Howell's spineflower, Mendocino spineflower

Habit Plants erect to spreading or decumbent, 0.5–3 × 0.1–6 dm, villous. Plants spreading or decumbent to somewhat erect, 0.3–1 × 1–5 dm, villous.
Leaves

basal or nearly so;

petiole 1–4(–7) cm;

blade oblanceolate, 1.5–5 × 0.2–0.7(–1) cm, villous.

basal or nearly so;

petiole 1–4 cm;

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

Inflorescences

with secondary branches not suppressed except in terminal clusters of involucres, green to reddish;

bracts 2, similar to proximal leaf blades only reduced, short-petiolate, becoming linear and aciculate at distal nodes, acerose, 1–5 cm × 2–5(–7) mm, awns absent.

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.

Involucres

1, greenish, cylindric, not ventricose, 2.5–4 mm, with white to pinkish, thin scarious margins restricted to basal portion of teeth, not corrugate, thinly pubescent abaxially;

teeth spreading, equal, 0.3–0.8(–1) mm;

awns uncinate with longer ones 0.7–1.3 mm and anterior one mostly 1–1.3 mm, these alternating with shorter (0.3–0.7 mm) ones.

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.

Flowers

slightly exserted;

perianth bicolored with floral tube white and tepals white to rose, cylindric, 2.5–4 mm, pubescent abaxially;

tepals connate 1/4 their length, monomorphic, oblanceolate to narrowly oblong, usually truncate to rounded and erose or denticulate apically, occasionally distinctly cuspidate;

stamens 9, included;

filaments distinct, 2–3.5 mm, glabrous;

anthers pink to red or maroon, oblong, 0.6–0.8 mm.

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.

Achenes

light brown, globose-lenticular, 3.5–4 mm.

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

2n

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

Chorizanthe robusta

Chorizanthe howellii

Phenology Flowering May–Jul.
Habitat Sandy places in coastal dunes and grassland communities
Elevation 0-20 m (0-100 ft)
Distribution
from USDA
wc Calif
[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.)

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.)

Key
1. Margins of involucres white; plants spreading or decumbent; sandy to gravelly places; Alameda and San Mateo counties s in mountains and near coast to n Monterey County
var. robusta
1. Margins of involucres rose-pink; plants erect; annual grasslands near Scotts Valley, Santa Cruz Mountains, Santa Cruz County
var. hartwegii
Source FNA vol. 5, p. 455. FNA vol. 5, p. 456.
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. spinosa, C. staticoides, C. stellulata, C. uniaristata, C. valida, C. ventricosa, C. watsonii, C. wheeleri, C. xanti
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
Subordinate taxa
C. robusta var. hartwegii, C. robusta var. robusta
Name authority Parry: Proc. Davenport Acad. Nat. Sci. 5: 176. (1889) Goodman: Ann. Missouri Bot. Gard. 21: 44, plate 3, fig. 1. (1934)
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