Cirsium pulcherrimum |
Cirsium joannae |
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Wyoming thistle |
Joanna's thistle |
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Habit | Perennials polycarpic, 15–60(–90) cm; deep-seated woody tap-roots and caudices. | Perennials, 100–150 cm; caudices taprooted. | ||||
Stems | 1–few, erect or ascending, arachnoid-tomentose or ± glabrate; branches 0–5+, usually in distal 1/2, ascending. |
1, fleshy, erect, openly branched in distal 1/2, glabrous; branches on distal stems several, ascending. |
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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. |
blades oblong, 10–50 × 6–12 cm, margins usually not strongly undulate, coarsely dentate or shallowly to deeply pinnatifid with 10–15 pairs of lobes, teeth or lobes ± closely spaced, not much overlapping, narrowly to broadly triangular, spiny-dentate or larger shallowly 3–5-lobed, main spines 2–12 mm, abaxial faces glabrous, adaxial glabrous; basal present at flowering, petiolate or spiny winged-petiolate; principal cauline many, well distributed, proximally ± winged-petiolate, distally sessile, gradually reduced, less divided, bases auriculate-claping and/or decurrent as spiny wings to 2 cm; distal much reduced. |
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Peduncles | 0–15 cm. |
0–2 cm Involucres green, ovoid to campanulate (not including spreading phyllary apices), 2.5–4 × 2.5–3.5 cm, appearing glabrous. |
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Involucres | ovoid to campanulate, 1.8–2.7 × 1–2 cm, thinly arachnoid-tomentose or glabrate. |
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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. |
lavender-pink, 20–26 mm, tubes 5–8.5 mm, throats 5.2–8 mm, lobes linear, 9–10 mm; style tips 3.5–4.2 mm, conspicuously exserted beyond corolla lobes. |
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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. |
in 5–7 series, unequal, outer longer than inner, bases short-appressed, abaxial faces without glutinous ridge, minutely scabridulous, apices green, thick, spreading to curved-ascending, proximally flattened, linear, spines stout, 5–12 mm; outer entire or pinnately spiny, inner entire, scabridulous-ciliolate; apices of inner flexuous, sometimes slightly expanded and minutely erose. |
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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. |
several–many, erect or nodding, usually sessile or short-pedunculate, crowded in subcaptitate or short, spiciform clusters at branch tips, collectively forming open, paniculiform arrays. |
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Cypselae | tan to dark brown, 5–6 mm, apical collars yellow, narrow; pappi 14–16 mm. |
dark brown, 4.5–5 mm, apical collars not differeniated; pappi ca. 20 mm. |
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2n | = 34. |
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Cirsium pulcherrimum |
Cirsium joannae |
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Phenology | Flowering summer (Aug–Sep). | |||||
Habitat | Hanging gardens with Lobelia, Abies, and Adiantum | |||||
Elevation | 1700 m (5600 ft) | |||||
Distribution |
CO; ID; MT; NE; UT; WY
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UT |
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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. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cirsium joannae is endemic to Zion National Park in southwestern Utah. It apears to be most closely related to C. rydbergii, which occurs in similar habitats in southeastern Utah and northeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 125. | FNA vol. 19, p. 163. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Carduus pulcherrimus | |||||
Name authority | (Rydberg) K. Schumann: Just’s Bot. Jahresber. 29(1): 566. (1903) | S. L. Welsh: in S. L. Welsh et al., Utah Fl. ed. 3, 168. (2003) | ||||
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