Cirsium occidentale var. coulteri

(Harvey & A. Gray) Jepson

Fl. W. Calif., 509. 1901.

Common names: Coulter’s thistle
IllustratedEndemicConservation concern
Basionym: Cirsium coulteri Harvey & A. Gray Mem. Amer. Acad. Arts, n. s. 4: 110. 1849
Treatment appears in FNA Volume 19. Treatment on page 138. Mentioned on page 137, 139.

Plants erect or bushy, usually 30–150+ cm, variably tomentose, sometimes ± glabrate. Leaf faces gray-tomentose or adaxial ± glabrate. Heads sometimes in tight clusters at ends of peduncles, usually long-pedunculate, usually elevated well above proximal leaves. Involucres usually about as wide as tall, 4–5 cm diam., densely arachnoid with fine trichomes connecting tips of adjacent phyllaries. Phyllaries subequal, outer ascending to spreading or reflexed, mid apices ascending to stiffly spreading, straight, acicular, usually 1.5–3 × 1–2 mm. Corollas light purple to rich reddish purple, usually 25–33 mm.


Phenology: Flowering spring–summer (Mar–Jun).
Habitat: Coastal slopes and ridges, dunes, coastal scrub, grassland, oak woodlands
Elevation: 0–700 m

Discussion

Of conservation concern.

Variety coulteri grows in the coastal zone of central and southern California. The epithet coulteri was for many years misapplied by California botanists. W. L. Jepson ([1923–1925]) used it at the varietal level for a range of plants that included parts of what I am calling vars. venustum and californicum. P. A. Munz (1959) and various other authors recognized Cirsium coulteri as a species, primarily in the context that I recognize as var. venustum. J. T. Howell (1959b) examined the type of C. coulteri and concluded that it and C. occidentale (in the strict sense) are synonymous. I have examined photos of the types of both C. occidentale and C. coulteri and have reached a different conclusion. The type of C. occidentale (BM) has heads with ± imbricate, comparatively short phyllary appendages. The type of C. coulteri (TCD) has long, acicular, subequal phyllaries. D. J. Keil and C. E. Turner (1993) treated the plants with the two head types all as var. occidentale, but I believe it is preferable to recognize separate varieties. Some intermediates are known, but var. coulteri is usually readily separable from var. occidentale.

Selected References

None.

Lower Taxa

None.

"fine" 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 +
(Harvey & A. Gray) Jepson +
sessile +  and petiolate +
spiny-winged +
not +, decurrent +  and tapered +
Cirsium coulteri +
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 +
Coulter’s thistle +
actinomorphic +
white +  and lavender pink rose-purple or red +
light purple;rich reddish purple +
2.5 cm25 mm <br />0.025 m <br /> (3.3 cm33 mm <br />0.033 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
0–700 m +
glabrate +  and white-tomentose +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Coastal slopes and ridges, dunes, coastal scrub, grassland, oak woodlands +
long-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 +
1.5 cm15 mm <br />0.015 m <br /> (8 cm80 mm <br />0.08 m <br />) +
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 +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
ascending +  and spreading or reflexed +
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–Jun). +
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 +
Illustrated +, 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. coulteri +
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 />) +
plant +  and bushy +
glabrate +  and tomentose +