Cirsium carolinianum |
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Carolina or purple or soft or smallhead thistle, Carolina thistle, soft thistle |
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Habit | Biennials, 50–180 cm; taproots short with many slender, fibrous lateral roots. |
Stems | usually single, erect, glabrous to ± tomentose, sometimes sparsely villous with septate trichomes; branches few, usually distal, ascending. |
Leaves | blades linear to oblanceolate or elliptic, 10–30 × 1–5 cm, unlobed and spinulose to irregularly dentate or pinnatifid, lobes narrowly to broadly triangular, sometimes coarsely toothed or lobed toward base, acuminate, main spines slender, 1–5 mm, abaxial faces gray-tomentose, adaxial glabrous or sparsely villous with septate trichomes; basal often present at flowering, petioles slender, winged, bases long-tapered; principal cauline relatively few (10–25), petiolate or distal sessile, mostly restricted to proximal 1/2 of stems, progressively reduced distally, bases tapered, not decurrent; distal cauline widely separated, linear to narrowly elliptic, reduced, becoming ± bractlike, merely spinulose to irregularly dentate or shallowly lobed. |
Peduncles | slender, 1–15 cm (not overtopped by distal leaves). |
Involucres | narrowly ovoid to campanulate, 1.2–2 × 1.2–2 cm, thinly arachnoid-ciliate. |
Corollas | pink-purple (white), 15–20 mm, tubes 5–9 mm, throats 5–7 mm (noticeably wider than tubes), lobes 4–5 mm; style tips 4 mm. |
Phyllaries | in 7–10 series, imbricate, green, linear to lanceolate (outer) or linear to linear-lanceolate (inner), abaxial faces with narrow, glutinous ridge; outer and middle ascending to appressed, bodies entire, apices widely spreading (at least the outer), spines ascending to spreading (at least the outer), slender, 1–4 mm; apices of inner phyllaries flat, often twisted, acuminate. |
Heads | (1–)2–9(–many), in paniculiform arrays. |
Cypselae | light brown, 3–4 mm, apical collars yellowish, 0.5–1 mm; pappi 12–14 mm. |
2n | = 20, 22. |
Cirsium carolinianum |
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Phenology | Flowering spring–summer (Apr–Jul). |
Habitat | Wooded areas, openings, fields, roadsides |
Elevation | 50–300 m (200–1000 ft) |
Distribution |
AL; AR; GA; IL; IN; KY; LA; MO; MS; NC; OH; OK; SC; TN; TX
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Discussion | Cirsium carolinianum is widely distributed in the southeastern United States: on the Gulf coastal plain from Texas to Alabama north through the Ouachita and Ozark highlands to southeastern Missouri; in the Ohio River Valley from southernmost Illinois to southern Ohio and northern Kentucky; and in the southern Appalachians and Piedmont from Alabama and Tennessee to southern Virginia. Cirsium carolinianum, though widespread, is a taxon of conservation concern over part of its range. The replacement of open woods by dense forests brought about by fire suppression has greatly reduced available habitat. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 118. |
Parent taxa | Asteraceae > tribe Cardueae > Cirsium |
Sibling taxa | |
Synonyms | Carduus carolinianus, C. flaccidum |
Name authority | (Walter) Fernald & B. G. Schubert: Rhodora 50: 229. (1948) |
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