Cirsium lecontei |
Cirsium hydrophilum |
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black or Le Conte's thistle, Le Conte's thistle |
Mt. Tamalpais thistle, Suisun thistle |
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Habit | Perennials but sometimes appearing biennial, 35–110 cm; taproots, sometimes with root sprouts. | Biennials or monocarpic perennials, 100–220 cm; taprooted. | ||||
Stems | 1–few, erect, distal 1/2 nearly naked, loosely arachnoid; branches 0–5(–10), stiffly ascending. |
1–several, erect, (hollow), openly branched distally or throughout, thinly arachnoid with fine, non-septate trichomes, glabrate. |
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Leaves | blades linear to oblong or narrowly elliptic, 15–25 × 1–4 cm, coarsely toothed to shallowly pinnatifid, lobes undivided or coarsely few-toothed, main spines 3–6 mm, abaxial faces often ± glabrate, loosely arachnoid when young, adaxial glabrous or sparingly villous with coarse, multicellular trichomes; basal sometimes absent at flowering, petiolate; principal cauline sessile, progressively reduced distally, bases clasping or ± decurrent; distal cauline few, widely separated, bractlike. |
blades elliptic to broadly oblanceolate, 10–40+ cm, pinnatifid 1/2–2/3 distance to midveins, larger usually with broad sinuses, lobes broad, few lobed or dentate, main spines 2–9 mm, abaxial faces ± gray-tomentose, sometimes ± glabrate, adaxial thinly arachnoid-tomentose, soon glabrescent; basal present or withered at flowering, winged-petiolate; principal cauline sessile, progressively reduced distally, bases auriculate-clasping or shortly decurrent; distal cauline reduced, bractlike, often spinier than proximal. |
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Peduncles | 5–30 cm (elevated above cauline leaves, not subtended by ring of involucre-like bracts). |
0–10+ cm. |
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Involucres | broadly cylindric to campanulate, 2.5–4 × 1.5–4 cm, loosely arachnoid, ± glabrate. |
ovoid to campanulate, 1.5–2.5 × 1.5–3 cm, thinly arachnoid, glabrate. |
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Corollas | pink-purple, 22–45 mm, tubes 10–23 mm, throats 8–14 mm, lobes 7–10 mm; style tips 4–5 mm. |
pale rose-purple, 18–23 mm, tubes 8–10 mm, throats 5–6 mm, lobes 5–7 mm; style tips 3.5–4.5 mm. |
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Phyllaries | in 6–10 series, imbricate, ovate or lanceolate (outer) to linear-lanceolate (inner), abaxial faces with prominent glutinous ridge, outer and middle tightly appressed, margins spinulose-serrulate, spines ascending, 0.5–2 mm; apices of inner flat, linear- acuminate. |
in 6–9 series, imbricate, dark green to brownish, lanceolate (outer) to linear (inner), abaxial faces with narrow glutinous ridge; outer and middle appressed, apices spreading, finely serrulate, spines slender, 1–2 mm; apices of inner erect, ± flexuous. |
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Heads | borne singly or less commonly 2–5(–10) in open, corymbiform arrays. |
borne singly or few at branch tips, sometimes subtended by clustered, ± leafy bracts, collectively forming ± open, many-headed paniculiform arrays. |
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Cypselae | light brown, 5–5.75 mm, apical collars paler than body, ca. 0.75 mm; pappi 20–40 mm. |
dark brown to black, 4–5 mm, collars very narrow, stramineous; pappi ca. 15 mm. |
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2n | = 28, 32. |
= 32. |
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Cirsium lecontei |
Cirsium hydrophilum |
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Phenology | Flowering spring–summer (May–Aug). | |||||
Habitat | Sandy pinelands of coastal plain, often in damp soil | |||||
Elevation | 0–150 m (0–500 ft) | |||||
Distribution |
AL; FL; LA; MS; NC; SC
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CA
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Discussion | Of conservation concern. Cirsium lecontei occurs on the southern coastal plain. R. J. Moore and C. Frankton (1969) suggested that it originated as a derivative of ancient hybridization between the ancestors of C. horridulum and C. nuttallii. They further suggested a relationship between C. lecontei and C. grahamii of Arizona and hypothesized an ancient dispersal from the southeastern coastal plain to the western cordillera. Although such relationships are possible, I have seen little support for them in my examination of these taxa. I think it is more likely that C. lecontei, C. horridulum, and C. nuttallii originated from a common stock, and that the resemblances between C. lecontei and C. grahamii are a result of convergence. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 114. | FNA vol. 19, p. 132. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Carduus lecontei | Carduus hydrophilus, C. vaseyi var. hydrophilum | ||||
Name authority | Torrey & A. Gray: Fl. N. Amer. 2: 458. (1843) | (Greene) Jepson: Fl. W. Calif., 507. (1901) | ||||
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