Cirsium occidentale var. compactum

Hoover

Vasc. Pl. San Luis Obispo Co., 310. 1970.

Common names: Compact cobwebby thistle
EndemicConservation concern
Treatment appears in FNA Volume 19. Treatment on page 139. Mentioned on page 137.

Plants compactly branched, forming low rounded mounds, 5–100 cm, densely gray-tomentose. Leaf faces gray-tomentose or adaxial ± glabrate. Heads borne singly or in ± tight clusters, short-pedunculate, closely subtended and often overtopped by basal and large cauline leaves. Involucres wider than long, 5–8 cm diam., densely arachnoid with fine trichomes connecting tips of adjacent phyllaries. Phyllaries: imbricate to subequal, outer and mid apices ± spreading, straight, usually 1–2 cm × usually 1–2 mm. Corollas dark rose-purple, 25–30 mm. 2n = 30.


Phenology: Flowering winter–summer (Feb–Jul).
Habitat: Coastal sea bluffs, dunes in grassland and coastal scrub
Elevation: 0–50 m

Discussion

Variety compactum is locally common along the immediate coast of northern San Luis Obispo County and formerly ranged as far north as San Francisco. Populations referable to this race occur on the California Channel Islands and on the mainland in Monterey County. Because of the very narrow ecologic zone occupied by these plants they are particularly vulnerable to habitat loss. Variety compactum is closely related to vars. occidentale and coulteri.

of conservation concern

Selected References

None.

Lower Taxa

None.

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

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 +
Hoover +
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 +
Compact cobwebby thistle +
actinomorphic +
dark rose-purple +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
0–50 m +
glabrate +  and white-tomentose +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Coastal sea bluffs, dunes in grassland and coastal scrub +
short-pedunculate +
in more or less tight clusters +  and singly +
indeterminate +
each +  and sessile +
5 cm50 mm <br />0.05 m <br /> (8 cm80 mm <br />0.08 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 gray-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 +
rounded +
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 winter–summer (Feb–Jul). +
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 +
Vasc. Pl. San Luis Obispo Co., +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
Endemic +  and Conservation concern +
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. compactum +
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 />) +