Cirsium pulcherrimum

(Rydberg) K. Schumann

Just’s Bot. Jahresber. 29(1): 566. 1903.

Common names: Wyoming thistle
Endemic
Basionym: Carduus pulcherrimus Rydberg Bull. Torrey Bot. Club 28: 510. 1901
Treatment appears in FNA Volume 19. Treatment on page 125. Mentioned on page 98, 105, 108, 126.

Perennials polycarpic, 15–60 (–90) cm; deep-seated woody taproots and caudices. Stems 1–few, erect or ascending, arachnoid-tomentose or ± glabrate; branches 0–5+, usually in distal 1/2, ascending. Leaves: blades linear to oblong, oblanceolate, or elliptic, 5–25 × 0.6–7 cm, unlobed and merely spinulose or spiny-dentate to regularly pinnatifid, lobes 5–8 (–many) pairs, well separated, usually with broad, U-shaped sinuses to crowded, linear to triangular-ovate, ascending-spreading to retrorse, merely spinulose to coarsely dentate or few lobed, main spines 2–7 mm, ± slender, abaxial faces gray to white, usually densely arachnoid-tomentose, sometimes ± glabrate, sometimes villous with septate trichomes along veins, adaxial green, glabrous or less commonly thinly to densely gray-tomentose; basal often present at flowering, spiny winged-petiolate; principal cauline well distributed, gradually reduced distally, proximal usually winged-petiolate, mid and distal sessile, bases decurrent as spiny wings 1.5–3.5 cm; distalmost reduced, ± bractlike. Heads 1–few, borne singly or in 2–3-headed clusters in ± congested flat-topped or racemiform arrays at tips of main-stem and branches, sometimes also in distal axils. Peduncles 0–15 cm. Involucres ovoid to campanulate, 1.8–2.7 × 1–2 cm, thinly arachnoid-tomentose or glabrate. Phyllaries in 6–7 series, ± imbricate, green or with dark subapical patch or appendage, linear to linear-lanceolate, margins entire, abaxial faces with narrow glutinous ridge; outer and middle bases appressed, apical appendages spreading to stiffly ascending, linear-lanceolate to acicular, entire, spines spreading or ascending, stout, 2–7 mm, often flattened; apices of inner stiffly erect or sometimes flexuous, narrow, flat. Corollas pink to purple (creamy white), 18–25 mm, tubes 7–9 mm, throats 5.5–7.5 mm, lobes 4–8 mm; style tips 3–5.5 mm. Cypselae tan to dark-brown, 5–6 mm, apical collars yellow, narrow; pappi 14–16 mm. 2n = 34.

Distribution

V19-87-distribution-map.gif

Colo., Idaho, Mont., Nebr., Utah, Wyo.

Discussion

Varieties 2 (2 in the flora).

Cirsium pulcherrimum is closely related to C. clavatum. In southeastern Wyoming and northern Colorado some plants combine foliage and involucral characters of C. pulcherrimum var. pulcherrimum and C. clavatum var. americanum. The inheritance of these characters needs to be examined at the population level to determine whether the intermediates are hybrids or the products of past introgression or incomplete differentiation.

Selected References

None.

Key

1 Distal leaf face gray- to white-tomentose; cypselae without stramineous apical collar Cirsium pulcherrimum var. aridum
1 Distal leaf face usually green, glabrous or ± glabrate, but sometimes persistently tomentose; cypselae often with narrow stramineous apical collar Cirsium pulcherrimum var. pulcherrimum

"fine" is not a number."broad" is not a number.

... more about "Cirsium pulcherrimum"
gray +  and white +
villous +, glabrate +  and arachnoid-tomentose +
gray-tomentose +, less commonly +  and glabrous +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
spreading +  and stiffly ascending +
linear-lanceolate +  and acicular +
indeterminate +  and determinate +
flat-topped +
David J. Keil +
(Rydberg) K. Schumann +
winged-petiolate +
decurrent +
Carduus pulcherrimus +
compound +  and simple +
5 cm50 mm <br />0.05 m <br /> (25 cm250 mm <br />0.25 m <br />) +
unlobed;linear;oblong oblanceolate or elliptic +
0.6cm;7cm +
10-nerved or 20-nerved +  and rugose +
tawny +  and white +
deep-seated +
Wyoming thistle +
actinomorphic +
pink +  and purple +
1.8 cm18 mm <br />0.018 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
tan +  and dark-brown +
compressed +  and ovoid +
fertile +  and bisexual +
Colo. +, Idaho +, Mont. +, Nebr. +, Utah +  and Wyo. +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
in 2-3-headed clusters in more or less congested flat-topped or racemiform arrays +  and singly +
indeterminate +
each +  and sessile +
1.8 cm18 mm <br />0.018 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
glabrate +  and arachnoid-tomentose +
ovoid;campanulate +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
ascending-spreading;retrorse +
linear +  and triangular-ovate +
slender +
lobed +, few +  and dentate +
0.2 cm2 mm <br />0.002 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
usually lobed +  and dissected +
2-carpellate +
persistent +
1.4 cm14 mm <br />0.014 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
middle +  and outer +
weakly to strongly +
papillate +  and smooth +
Just’s Bot. Jahresber. +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
ascending +  and spreading +
flattened +
0.2 cm2 mm <br />0.002 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
spiny-winged +, simple +  and branched +
ascending +  and erect +
1 +  and few +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.3 cm3 mm <br />0.003 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
Compositae +
deep-seated +
Cirsium pulcherrimum +
species +
cylindric +
expanded +
0.55 cm5.5 mm <br />0.0055 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
bristly-dentate to coarsely +
slender +
0.7 cm7 mm <br />0.007 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
60 cm600 mm <br />0.6 m <br /> (90 cm900 mm <br />0.9 m <br />) +
15 cm150 mm <br />0.15 m <br /> (60 cm600 mm <br />0.6 m <br />) +
tree +, vine +, shrub +  and subshrub +
1.5 cm15 mm <br />0.015 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +