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Anderson's thistle, rose thistle

Adobe Hills thistle, Rocky Mountain thistle

Habit Perennials (but often appearing biennial), (15–)40–70(–100) cm; rootstocks producing erect, taprooted caudices and rosettes. Biennials, slender, 20–100 cm; taprooted.
Stems

usually 1, erect, subglabrous to puberulent and/or tomentose;

branches 0–several, stiffly ascending.

usually 1, erect, thinly arachnoid-tomentose, sparsely pilose distally with short, jointed trichomes;

branches few to many, often arising from proximal nodes, ascending.

Leaves

blades ± elliptic, 8–35 × 4–8 cm, divided about halfway to midveins, lobes spreading, triangular, coarsely dentate or with a few broad lobes, obtuse to acute, main spines 1–5 mm, abaxial faces green or gray, thinly tomentose, adaxial green and glabrous to sparingly pilose;

basal often present at flowering, spiny winged-petiolate;

main cauline reduced distally, bases clasping;

distal much reduced, linear-oblong, usually less deeply lobed and often spinier than proximal.

blades oblong to elliptic, 15–30 × 2–6 cm, often unlobed and merely spinulose or spiny-dentate, sometimes pinnatifid ca. halfway to midveins, lobes separated by broad sinuses, undivided to coarsely few-dentate, main spines slender, 2–5(–10) mm, abaxial faces ± persistently thinly gray-tomentose, adaxial green, glabrous to thinly tomentose, sometimes sparsely pilose on midveins;

basal sometimes present at flowering, sessile or short winged-petiolate;

principal cauline sessile, progressively reduced, becoming bractlike distally, mid and distal bases broadly clasping;

distal reduced to linear or lanceolate bracts.

Peduncles

0–20 cm.

(0–)3–20 cm.

Involucres

broadly cylindric to narrowly campanulate, 3–5 × 2–4 cm, loosely arachnoid or ± glabrous, finely short-ciliate.

hemispheric to subspheric, 1.3–2.5 × (1–)1.5–2.5 cm, glabrous to loosely floccose.

Corollas

red to reddish purple, 30–45 mm, tubes 10–20 mm, throats 10–16 mm, lobes 9–11 mm;

style tips 3.5–5 mm.

lavender to reddish purple, (16–)19–22 mm, tubes 6–9 mm, throats 5–8 mm, lobes 5–7 mm, style tips 5–6 mm.

Phyllaries

in 6–8 series, imbricate, outer green, inner purple to red, linear-lanceolate (outer) to linear (inner), abaxial faces without glutinous ridge;

outer and mid bodies short, appressed, entire or spinulose-ciliate, apices long-spreading to ascending, entire or spinulose-ciliate or rarely with expanded, fringed appendages, spines straight, weak, 1–3 mm;

apices of inner red to purple, straight or rarely twisted, long, flat, entire.

in 5–8(–10) series, strongly imbricate, green with darker green to brown subapical patch, broadly ovate or oblong (outer) to lanceolate (inner), abaxial faces with prominent to obscure glutinous ridge;

outer and middle appressed, spines or terminal appendages spreading to reflexed, bodies entire or with expanded, ± scarious, ± pectinately fringed terminal appendages, tips merely mucronate or with weak spines spreading to reflexed, 1–3 mm;

apices of inner often flexuous, flat, scarious, serrulate to expanded and pectinately fringed.

Heads

1–6, borne singly or in corymbiform, racemiform, or spiciform arrays.

few–many, in ± openly branched corymbiform or paniculiform arrays;

not closely subtended by clustered leafy bracts.

Cypselae

brown, 6–7 mm, apical collars narrow;

pappi 25–40 mm.

dark brown, 4–5 mm, apical collars stramineous or not differently colored, very narrow;

pappi 15–17 mm.

2n

= 32, 64.

Cirsium andersonii

Cirsium perplexans

Phenology Flowering summer (Jul–Sep). Flowering spring–summer (May–Aug).
Habitat Moist to dry soils, openings in montane woodlands, montaine coniferous forests, aspen groves Barren shale hillsides, gypsiferous clay soils, open, nearly unvegetated sites in areas of pinyon-juniper woodlands, sagebrush scrub, saltbush scrub, or Gambel oak brush, roadsides
Elevation 1100–2900 m (3600–9500 ft) 1800–2100 m (5900–6900 ft)
Distribution
from FNA
CA; ID; NV
[WildflowerSearch map]
[BONAP county map]
from FNA
CO
[BONAP county map]
Discussion

Cirsium andersonii grows in the Cascade Range of northern California south through the Sierra Nevada of eastern California and western Nevada. It has been reported from the mountains of southwestern Idaho, but I have not seen specimens from there.

Heads of Cirsium andersonii are actively visited by hummingbirds as well as a variety of insects (P. L. Barlow-Irick 2002).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Cirsium perplexans occurs in a few scattered sites at relatively low elevations in the Rocky Mountains of west-central Colorado. In view of this restricted distribution, the common name used by governmental agencies, Rocky Mountain thistle, is misleading; one would expect a species so named to be widely distributed in the Rocky Mountains. The name Adobe Hills thistle is descriptive of the habitat.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 19, p. 145. FNA vol. 19, p. 128.
Parent taxa Asteraceae > tribe Cardueae > Cirsium Asteraceae > tribe Cardueae > Cirsium
Sibling taxa
C. altissimum, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. engelmannii, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. perplexans, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
C. altissimum, C. andersonii, C. andrewsii, C. arizonicum, C. arvense, C. barnebyi, C. brevifolium, C. brevistylum, C. canescens, C. carolinianum, C. ciliolatum, C. clavatum, C. crassicaule, C. cymosum, C. discolor, C. douglasii, C. drummondii, C. eatonii, C. edule, C. engelmannii, C. flodmanii, C. foliosum, C. fontinale, C. grahamii, C. helenioides, C. hookerianum, C. horridulum, C. hydrophilum, C. inamoenum, C. joannae, C. kamtschaticum, C. lecontei, C. longistylum, C. mohavense, C. muticum, C. neomexicanum, C. nuttallii, C. occidentale, C. ochrocentrum, C. ownbeyi, C. palustre, C. parryi, C. pitcheri, C. praeteriens, C. pulcherrimum, C. pumilum, C. quercetorum, C. remotifolium, C. repandum, C. rhothophilum, C. rydbergii, C. scariosum, C. texanum, C. tracyi, C. turneri, C. undulatum, C. vinaceum, C. virginianum, C. vulgare, C. wheeleri, C. wrightii
Synonyms Cnicus andersonii Carduus perplexans, C. vernale
Name authority (A. Gray) Petrak: Bot. Tiddsskr. 31: 68. (1911) (Rydberg) Petrak: Beih. Bot. Centralbl. 35(2): 441. (1917)
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