Flora of North America species comparison

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Cirsium occidentale var. venustum
Photo is of parent taxon

cobwebby thistle, Venus thistle
Habit Plants usually erect, usually 50–300 cm, variably tomentose, sometimes ± glabrate.
Involucres

usually longer than wide, 2–6 cm, subglabrous to densely arachnoid, usually without fine trichomes connecting tips of adjacent phyllaries.
Corollas

usually ± red (white, pink, rarely purple), 23–35 mm.
Phyllaries

imbricate, outer and mid apices ascending to rigidly spreading or reflexed, straight, 5–20+ × usually 2–3 mm.
Heads

sometimes in tight clusters at ends of peduncles, usually long-pedunculate, elevated well above proximal leaves.
2n

= 30.

Cirsium occidentale var. venustum
Phenology Flowering spring–summer (Apr–Jul).
Habitat Foothill oak-pine woodlands, grasslands, chaparral, pinyon-juniper woodlands, Joshua tree woodlands, roadsides
Elevation 200–2300 m (700–7500 ft)
Distribution
from FNA
CA; NV
[BONAP county map]
Discussion

Variety venustum has the widest ecological range of the races of C. occidentale. Populations occur within a few miles of the California coast in the North and South Coast Ranges and western Transverse Range and range eastward across the state into scattered sites in the Sierra Nevada to the higher elevations of the arid mountains of the western Mojave Desert and adjacent areas of the southwestern Great Basin Desert. Most populations of these plants can be recognized by their striking red to reddish pink corollas. The heads are sometimes visited by hummingbirds as well as by a variety of insects. Intermediates have been documented between var. venustum and vars. californicum and candidissimum.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 19, p. 140.
Parent taxa Asteraceae > tribe Cardueae > Cirsium > Cirsium occidentale
Sibling taxa
C. occidentale var. californicum, C. occidentale var. candidissimum, C. occidentale var. compactum, C. occidentale var. coulteri, C. occidentale var. lucianum, C. occidentale var. occidentale
Synonyms Carduus venustus, C. occidentale subsp. venustum, C. proteanum
Name authority (Greene) Jepson: Man. Fl. Pl. Calif., 1167. (1925)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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