Cirsium inamoenum

(Greene) D. J. Keil

Sida 21: 214. 2004.

Endemic
Basionym: Carduus inamoenus Greene Fl. Francisc., 479. 1897,
Treatment appears in FNA Volume 19. Treatment on page 134. Mentioned on page 105, 106, 108, 135, 136, 141, 151, 153.

Biennials or monocarpic perennials, 20–100 cm; deeply taprooted. Stems 1–several, erect, thinly to densely gray-tomentose with fine, non-septate trichomes; branches 0–many, ascending. Leaves: blades oblanceolate or elliptic, 10–35 × 1–7 cm, unlobed and spinulose to dentate or deeply pinnatifid, usually 5–8 pairs of lobes, well separated, linear to lance-triangular, spinulose to few toothed or lobed, main spines 2–7 mm, abaxial faces densely gray-tomentose or sometimes ± glabrate, adaxial gray to ± green, thinly tomentose or ± glabrate; basal sometimes present at flowering, narrowly winged-petiolate; principal cauline well distributed, gradually reduced, sometimes spinier than basal; proximal winged-petiolate, mid sessile, bases spiny-winged, decurrent 1–3 cm; distal becoming bractlike, often unlobed or less deeply divided than proximal. Heads 1–many, in open corymbiform arrays or crowded near stem tips. Peduncles 0–25 cm. Involucres ovoid or hemispheric to campanulate, 2–3 × 1.5–5 cm, glabrous or loosely floccose to densely arachnoid. Phyllaries in 6–10 series, strongly imbricate or sometimes subequal, greenish to brown, ovate to linear-lanceolate (outer) to linear (inner), entire, abaxial faces with narrow or scarcely developed glutinous ridge; outer and mid appressed or apices ascending to spreading, linear, bodies entire, spines ascending to abruptly spreading, usually fine, 2–6 mm; apices of inner narrow, spine-tipped or spineless. Corollas dull white or faintly lavender-tinged to bright pink-purple, 19–31 mm, tubes 7–13 mm, throats 6.5–9.5 mm, lobes 4–8 mm; style tips 3.5–7 mm. Cypselae brown, 5–8 mm, apical collars not differentiated; pappi 12–25 mm. 2n = 32, 34, 36.

Distribution

V19-108-distribution-map.gif

Calif., Idaho, Nev., Oreg., Utah, Wash., Wyo.

Discussion

Varieties 2 (2 in the flora).

Cirsium inamoenum is a variable complex across the northern Great Basin and adjacent mountains. A. Cronquist (1994) treated this complex as a single species under the name C. subniveum without infraspecific taxa and including taxa that formerly had been assigned to C. utahense (e.g., J. T. Howell 1960b). Some populations consist of small-headed, white-flowered plants with strong involucres and short, appressed phyllaries. Others have larger heads, white or lavender to pink-purple corollas, and phyllaries with longer, ascending to spreading tips. My treatment of this complex as C. inamoenum is similarly inclusive as was Cronquist’s treatment of C. subniveum, except that I believe C. humboldtense, which Cronquist included, is probably a derivative of hybridization between C. subniveum and C. eatonii var. peckii. I have observed such hybrids on the slopes of Steens Mountain in Harney County, Oregon, and the type of C. humboldtense closely resembles some of the introgressants. I have examined several other specimens that are likely the products of hybridization of C. inamoenum with other varieties of C. eatonii.

I have chosen to recognize racial differentiation within Cirsium inamoenum at the rank of variety. The main difference between Cirsium inamoenum var. inamoenum and var. davisii is corolla color. Unfortunately this feature is sometimes difficult to determine on herbarium specimens, and many collectors fail to include corolla color on specimen labels. Some geographic overlap occurs between var. davisii, which has a distribution centered in northeastern Utah, southeastern Idaho, and adjacent southwestern Wyoming, and the more widespread var. inamoenum.

Plants of northeastern Oregon, southeastern Washington, and adjacent western Idaho often have large heads and densely tomentose foliage. These were named Cirsium wallowense by Peck. Similar plants occur sporadically in other portions of the range of Cirsium inamoenum var. inamoenum and I chose not to recognize these northwestern populations as a third variety. Additional study might clarify the relationships of these plants.

Some specimens of Cirsium inamoenum in central Nevada and Utah approach C. neomexicanum. It seems likely that these species have interacted in the past.

Selected References

None.

Key

1 Corollas white or pale lavender Cirsium inamoenum var. inamoenum
1 Corollas lavender to rich pink-purple Cirsium inamoenum var. davisii

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

... more about "Cirsium inamoenum"
36 +, 34 +  and 32 +
glabrate +  and gray-tomentose +
gray;more or less green +
glabrate +  and tomentose +
short-tailed +
spineless +  and spine-tipped +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
erect +  and spreading +
innermost +
scarious +
not differentiated +
corymbiform +  and open +
indeterminate +  and determinate +
David J. Keil +
(Greene) D. J. Keil +
winged-petiolate +
spiny-winged +
decurrent +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Carduus inamoenus +
compound +  and simple +
10 cm100 mm <br />0.1 m <br /> (35 cm350 mm <br />0.35 m <br />) +
linear;lance-triangular spinulose +
1cm;7cm +
10-nerved or 20-nerved +  and rugose +
tawny +  and white +
actinomorphic +
faintly lavender-tinged +  and bright pink-purple +
1.9 cm19 mm <br />0.019 m <br /> (3.1 cm31 mm <br />0.031 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
less deeply divided +, unlobed +  and bractlike +
Calif. +, Idaho +, Nev. +, Oreg. +, Utah +, Wash. +  and Wyo. +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
indeterminate +
each +  and sessile +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
loosely floccose +  and densely arachnoid +
hemispheric;campanulate +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
deltate +, usually narrowly triangular +  and more or less linear +
0.2 cm2 mm <br />0.002 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
entire +  and dentate +
usually lobed +  and dissected +
ascending +  and spreading +
2-carpellate +
pinnatifid +  and dentate +
persistent +
1.2 cm12 mm <br />0.012 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0 cm0 mm <br />0 m <br /> (25 cm250 mm <br />0.25 m <br />) +
middle +  and outer +
papillate +  and smooth +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
ascending +  and abruptly spreading +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
spiny-winged +, simple +  and branched +
1 +  and several +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Compositae +
Cirsium inamoenum +
species +
cylindric +
expanded +
0.65 cm6.5 mm <br />0.0065 m <br /> (0.95 cm9.5 mm <br />0.0095 m <br />) +
bristly-dentate to coarsely +
slender +
0.7 cm7 mm <br />0.007 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
perennial +  and biennial +
20 cm200 mm <br />0.2 m <br /> (100 cm1,000 mm <br />1 m <br />) +
tree +, vine +, shrub +  and subshrub +