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Cooper caulanthus, Cooper's jewel-flower, Cooper's wild cabbage

clasping leaf caulanthus, claspingleaf wild cabbage

Habit Annuals; puberulent or glabrous (trichomes simple and subappressed, and 2-rayed). Annuals; glabrous throughout.
Stems

erect to ascending (often flexuous, weak, often tangled with desert shrubs), usually branched distally, 1–8 dm, glabrous or puberulent.

erect, unbranched or branched distally, 0.4–11 dm.

Basal leaves

rosulate;

petiole 0.3–2.5 cm;

blade oblanceolate to spatulate, 0.7–6 cm × 2–27 mm, margins usually coarsely dentate or somewhat pinnatifid, rarely entire, (surfaces glabrous).

rosulate;

petiole 0.5–3 cm;

blade obovate to broadly oblanceolate, 1–7 cm × 5–37 mm, margins coarsely dentate.

Cauline leaves

(median) sessile;

blade lanceolate or oblong, 1.5–7.5 cm × 5–20 mm (smaller distally, base amplexicaul to sagittate), margins dentate or entire, (surfaces glabrous).

(median) sessile;

blade oblong to broadly ovate or obovate, 2–8 cm × 10–40 mm (smaller distally, base amplexicaul), margins coarsely dentate or entire.

Racemes

(lax), without a terminal cluster of sterile flowers.

(lax), without a terminal cluster of sterile flowers.

Flowers

sepals erect, (purplish or yellow-green), narrowly lanceolate, 3–6.5 × 0.8–1.5 mm (equal);

petals yellow-green to purplish (often with purple veins), 4.5–9 mm, blade 2–3 × 0.7–1.5 mm, not crisped, claw narrowly oblong-oblanceolate, 2.5–7 × 1–1.5 mm;

filaments slightly tetradynamous, median pairs 2–4.5 mm, lateral pair 1.5–3.5 mm;

anthers oblong, equal, 1.5–2 mm.

sepals erect, (dark maroon-purple or ochroleucous to yellowish), ovate to ovate-lanceolate, 4–9.2 × 2–4 mm (equal);

petals (abaxial pair) usually stramineous to yellowish green, rarely pale purple, (adaxial pair) purple, (slightly longer), 10–18 mm, blade 4–10 × 0.5–1.5mm, crisped, claw narrowly oblong-oblanceolate, 6–10 × 1–3 mm;

filaments in 3 unequal pairs, abaxial pair 3–7 mm, lateral pair 1–5 mm, adaxial pair 4.5–9 mm;

anthers oblong, unequal, 1–3.5 mm (adaxial pair smaller).

Fruiting pedicels

reflexed, 1–4.5 mm, usually glabrous, rarely puberulent.

divaricate to ascending, 2.5–19 mm.

Fruits

usually reflexed, rarely divaricate (often subfalcate), terete, 2–6 cm × 1.5–2.5 mm;

valves each with prominent midvein, (glabrous or puberulent);

ovules 24–48 per ovary;

style 0.2–2.7 mm;

stigma slightly 2-lobed.

divaricate to ascending (often distinctly curved), terete or slightly latiseptate, 4.5–14(–16.7) cm × 1–1.5 mm;

valves each with obscure midvein;

ovules 40–92 per ovary;

style 0–0.4 mm;

stigma subentire.

Seeds

1–2 × 1–1.2 mm.

1.4–2.2 × 0.9–1.2 mm.

2n

= 28.

= 28.

Caulanthus cooperi

Caulanthus amplexicaulis

Phenology Flowering (Jan-)Feb–Mar. Flowering Apr–Jul(-Aug).
Habitat Desert shrubs, woodlands Chaparral, montane forests, serpentine areas, granitic and shale scree
Elevation 600-2300 m (2000-7500 ft) 800-2900 m (2600-9500 ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Caulanthus cooperi is distributed in the Colorado and Mojave deserts in western Arizona, central and southern California, southern Nevada, and southern Utah.

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

Caulanthus amplexicaulis is known from Los Angeles, San Bernardino, Santa Barbara, and Ventura counties. The serpentine populations of Santa Barbara County have sepals that are ochroleucous to yellowish instead of the dark maroon ones found elsewhere in the species range. They were recognized by R. C. Rollins (1993) and R. E. Buck (1995) as var. barbarae. Both vars. barbarae and amplexicaulis form a distinct monophyletic clade but they are without reproductive barriers (A. E. Pepper and L. E. Norwood 2001). Some other species of Caulanthus show comparable or even greater variation in sepal color, and it might be more practical to treat var. barbarae as a color form.

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

Source FNA vol. 7, p. 680. FNA vol. 7, p. 679.
Parent taxa Brassicaceae > tribe Thelypodieae > Caulanthus Brassicaceae > tribe Thelypodieae > Caulanthus
Sibling taxa
C. amplexicaulis, C. anceps, C. barnebyi, C. californicus, C. coulteri, C. crassicaulis, C. flavescens, C. glaucus, C. hallii, C. heterophyllus, C. inflatus, C. lasiophyllus, C. lemmonii, C. major, C. pilosus, C. simulans
C. anceps, C. barnebyi, C. californicus, C. cooperi, C. coulteri, C. crassicaulis, C. flavescens, C. glaucus, C. hallii, C. heterophyllus, C. inflatus, C. lasiophyllus, C. lemmonii, C. major, C. pilosus, C. simulans
Synonyms Thelypodium cooperi, Guillenia cooperi C. amplexicaulis var. barbarae, Euklisia amplexicaulis, Pleiocardia magna, Streptanthus amplexicaulis, Streptanthus amplexicaulis var. barbarae
Name authority (S. Watson) Payson: Ann. Missouri Bot. Gard. 9: 293. (1923) S. Watson: Proc. Amer. Acad. Arts 17: 364. (1882)
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