Cirsium occidentale var. occidentale

Common names: Cobwebby thistle
Endemic
Treatment appears in FNA Volume 19. Treatment on page 137. Mentioned on page 138, 139, 140, 159, 161.

Plants erect, usually 30–150 cm or taller. Leaf faces usually densely tomentose abaxially, less so and sometimes glabrate adaxially. Heads usually long pedunculate, sometimes in tight clusters at ends of peduncles, elevated well above proximal leaves. Involucres usually wider than long, 4–5 cm diam., ± densely and persistently arachnoid with fine trichomes connecting tips of adjacent phyllaries. Phyllaries usually ± imbricate, outer ascending or spreading or reflexed, mid phyllary apices ascending to spreading, straight or distally curved, usually 1–2 cm × 1–2 mm. Corollas ± bright purple, usually 25–35 mm. 2n = 28, 29, 30.


Phenology: Flowering spring–summer (Mar–Jul).
Habitat: Coastal scrub, chaparral, oak woodlands, stabilized dunes, roadsides
Elevation: 0–200 m

Discussion

Variety occidentale occupies a variety of habitats in the coastal zone of southern and central California. Considerable variation occurs from population to population in head size, flower color, and pubescence. It sometimes occurs together with and appears to intergrade with var. coulteri. Where there has been no hybridization, the two may be strikingly dissimilar, but individuals of some populations cannot be assigned with confidence to either variety.

Selected References

None.

Lower Taxa

None.

"fine" is not a number."usually wider than long" is not a number.

30 +, 29 +  and 28 +
arachnoid-tomentose +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
deflexed +  and spreading or ascending +
innermost +
scarious +
not differentiated +
corymbiform +, paniculiform +, subcapitate +, spiciform +  and racemiform +
indeterminate +  and determinate +
David J. Keil +
(Nuttall) Jepson +
sessile +  and petiolate +
spiny-winged +
not +, decurrent +  and tapered +
Carduus occidentalis +
compound +  and simple +
6 cm60 mm <br />0.06 m <br /> (40 cm400 mm <br />0.4 m <br />) +
pinnatifid;oblong-elliptic;oblanceolate +
1.5cm;10cm +
10-nerved or 20-nerved +  and rugose +
ascending;spreading +
tawny +  and white +
Cobwebby thistle +
actinomorphic +
bright purple +
2.5 cm25 mm <br />0.025 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
0–200 m +
glabrate +  and white-tomentose +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Coastal scrub, chaparral, oak woodlands, stabilized dunes, roadsides +
pedunculate +
indeterminate +
each +  and sessile +
4 cm40 mm <br />0.04 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
ovoid;spheric +
sessile +  and petiolate +
glabrate +  and tomentose +
cauline +  and basal +
bristle-tipped +
with 1-2 pairs +  and undivided +
deltate +, usually narrowly triangular +  and more or less linear +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
entire +  and dentate +
usually lobed +  and dissected +
2-carpellate +
persistent +
1.5 cm15 mm <br />0.015 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1 cm10 mm <br />0.01 m <br /> (30 cm300 mm <br />0.3 m <br />) +
Flowering spring–summer (Mar–Jul). +
curved +  and straight +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
ascending +  and spreading +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
imbricate +  and adjacent +
middle +  and outer +
glabrate +  and glabrous +
papillate +  and smooth +
Fl. W. Calif., +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
spreading +  and reflexed +
0.1 cm1 mm <br />0.001 m <br /> (1 cm10 mm <br />0.01 m <br />) +
spiny-winged +, simple +  and branched +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Compositae +
Cirsium occidentale var. occidentale +
Cirsium occidentale +
variety +
cylindric +
expanded +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
bristly-dentate to coarsely +
slender +
0.8 cm8 mm <br />0.008 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
5 cm50 mm <br />0.05 m <br /> (400 cm4,000 mm <br />4 m <br />) +