Cirsium horridulum var. horridulum

Common names: Horrid thistle
Endemic
Basionym: Carduus spinosissimus Walter 1788
Synonyms: Carduus horridulum var. elliottii
Treatment appears in FNA Volume 19. Treatment on page 115. Mentioned on page 114, 116.

Plants 15–180 cm. Stems densely tomentose. Leaves: blades oblanceolate or oblongelliptic, 10–30 cm, shallowly to deeply pinnatifid, main spines mostly 5–10 mm, abaxial faces loosely tomentose. Heads 1–10. Involucres 4–5 × 5–7 cm, ± densely tomentose. Phyllaries: outer and middle bodies scabridulous or minutely spinulose, marginal spinules usually 1 mm or shorter. Corollas yellow or crimson to red-purple. 2n = 32, 34.


Phenology: Flowering winter–spring (Apr–Jun).
Habitat: Fields, meadows, pinelands, roadsides, often weedy, often in damp soil
Elevation: 0–300 m

Distribution

V19-63-distribution-map.gif

Ala., Conn., Del., Fla., Ga., La., Maine, Md., Mass., Miss., N.H., N.J., N.Y., N.C., Pa., R.I., S.C., Tenn., Tex., Va.

Discussion

Variety horridulum occurs on the Atlantic and Gulf coastal plains fom southern Maine to Florida and west to eastern Texas and into the piedmont in much of the southeastern United States. Artificial hybrids have been produced between var. horridulum and Cirsium repandum (R. J. Moore and C. Frankton 1969), and natural hybrids with C. pumilum var. pumilum have been reported.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

glabrous +  and more or less densely villous +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
subcapitate +  and corymbiform +
indeterminate +  and determinate +
David J. Keil +
Michaux +
winged-petiolate +
auriculate-clasping +
tapered +
Carduus spinosissimus +
compound +  and simple +
10 cm100 mm <br />0.1 m <br /> (40 cm400 mm <br />0.4 m <br />) +
pinnatifid;oblongelliptic;oblanceolate +
10 cm100 mm <br />0.1 m <br /> (30 cm300 mm <br />0.3 m <br />) +
2cm;10cm +
reddish-tinged +
10-nerved or 20-nerved +  and rugose +
spreading;ascending +
tawny +  and white +
? (?) +  and ? (?) +
Horrid thistle +
actinomorphic +
crimson +  and red-purple +
3 cm30 mm <br />0.03 m <br /> (4.7 cm47 mm <br />0.047 m <br />) +
straw-colored +  and tan +
compressed +  and ovoid +
fertile +  and bisexual +
Ala. +, Conn. +, Del. +, Fla. +, Ga. +, La. +, Maine +, Md. +, Mass. +, Miss. +, N.H. +, N.J. +, N.Y. +, N.C. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +  and Va. +
0–300 m +
gray-canescent +  and glabrous +
perennating +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Fields, meadows, pinelands, roadsides, often weedy, often in damp soil +
indeterminate +
each +  and sessile +
4 cm40 mm <br />0.04 m <br /> (5 cm50 mm <br />0.05 m <br />) +
hemispheric;campanulate +
5 cm50 mm <br />0.05 m <br /> (7 cm70 mm <br />0.07 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
lobed +  and spiny-dentate +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
entire +  and dentate +
setulose-ciliolate +
usually lobed +  and dissected +
2-carpellate +
persistent +
2.5 cm25 mm <br />0.025 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
0 cm0 mm <br />0 m <br /> (5 cm50 mm <br />0.05 m <br />) +
Flowering winter–spring (Apr–Jun). +
middle +  and outer +
papillate +  and smooth +
Fl. Bor.-Amer. +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
spiny-winged +, simple +  and branched +
1 +  and several +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Carduus horridulum var. elliottii +
Cirsium horridulum var. horridulum +
Cirsium horridulum +
variety +
cylindric +
expanded +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
bristly-dentate to coarsely +
slender +
1.1 cm11 mm <br />0.011 m <br /> (3 cm30 mm <br />0.03 m <br />) +
perennial +  and biennial +
appressed-ascending +
15 cm150 mm <br />0.15 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +