Cirsium crassicaule |
Cirsium andrewsii |
|
---|---|---|
slough thistle |
Franciscan thistle |
|
Habit | Annuals or biennials, (60–)100–300 cm; taprooted. | Biennials (or short–lived monocarpic perennials), 60–200 cm; taprooted. |
Stems | usually 1, erect, stout, (hollow, 2–10 cm diam. at base), openly branched distally, thinly arachnoid, villous with jointed trichomes, at least proximally. |
several, erect to spreading, thinly arachnoid, soon glabrous; branches ± fleshy, usually much branched proximally, spreading to ascending. |
Leaves | blades elliptic to broadly oblanceolate, 15–70 × 30–150+ cm, flat, pinnatifid 1/2–2/3 distance to midvein, larger usually with broad sinuses, lobes broad, few lobed or dentate, main spines 3–8 mm, abaxial faces gray-tomentose, adaxial thinly arachnoid-tomentose, sometimes midveins with jointed trichomes; basal present or withered at flowering, winged-petiolate; principal cauline sessile, progressively reduced distally, bases clasping or short-decurrent 1–2 cm; distal cauline reduced, becoming bractlike, sometimes spinier than proximal. |
blades ± elliptic, 30–75 × 10–20 cm, shallowly to deeply pinnatifid, lobes oblong to ovate, unlobed or with several prominent secondary lobes or large teeth, obtuse to acute, main spines 2–7 mm, abaxial gray arachnoid-tomentose, adaxial faces thinly arachnoid, glabrate; basal often present at flowering, spiny winged-petiolate; principal cauline sessile, bases clasping with broad, spiny-margined auricles, reduced distally, spinier than proximal; distal much reduced, spines 7–20 mm. |
Peduncles | 0–15 cm. |
0–7 cm. |
Involucres | ovoid to campanulate, 1.5–3 × 1.5–3 cm, ± glabrous. |
ovoid to hemispheric or campanulate, 1.5–3 × 1.5–5 cm, sparsely to densely arachnoid, finely short-ciliate. |
Corollas | pale rose-purple (white), 19–26 mm, tubes 9–12 mm, throats 4–6 mm, lobes 5–9 mm; style tips 3.5–4.5 mm. |
dark reddish purple, 17–24 mm, tubes 8–11 mm, throats 3.5–6 mm, lobes 5–7 mm; style tips 3–4 mm. |
Phyllaries | in 5–7 series, weakly unequal, dark green to brownish, lanceolate (outer) to linear (inner), abaxial faces without (or with very obscure) glutinous ridge; outer and middle appressed or apices spreading, at least outer irregularly spiny-fringed, finely serrulate, spines slender, 3–5 mm; apices of inner erect, abaxial faces gray-tomentose, ± twisted. |
in ca. 6 series, dark green or brown or with stramineous margins and a darker central zone, imbricate, linear-lanceolate (outer) to linear (inner), abaxial faces without glutinous ridge; outer and mid bodies appressed, spiny-ciliate, apices long-spreading to ascending long-acuminate, spines straight, stout, 5–15 mm; apices of inner straight or twisted, long, entire, flat or spine-tipped. |
Heads | 1–several at branch tips, closely subtended by clustered leafy bracts or not, collectively forming open, corymbiform or paniculiform arrays. |
several–many, in congested corymbiform arrays. |
Cypselae | dark brown, 5–5.5 mm, collars narrow, ± stramineous; pappi 15–20 mm. |
dark brown, 4–5 mm, apical collars narrow; pappi 15 mm. |
2n | = 32. |
= 32. |
Cirsium crassicaule |
Cirsium andrewsii |
|
Phenology | Flowering spring (Apr–Jun). | Flowering spring–summer (May–Sep). |
Habitat | Freshwater marshes, canal banks | Headlands, ravines, seeps near coast, sometimes on serpentine |
Elevation | 5–100 m (0–300 ft) | 0–100 m (0–300 ft) |
Distribution |
CA |
CA
|
Discussion | Cirsium crassicaule is known only from a few sites in the San Joaquin Valley. Some populations are threatened by habitat modification and development pressures. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Cirsium andrewsii occurs along the coast of north-central California from San Mateo to Marin counties. It reportedly hybridizes with C. quercetorum (F. Petrak 1917; J. T. Howell 1960b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 132. | FNA vol. 19, p. 141. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Carduus crassicaulis | Cnicus andrewsii |
Name authority | (Greene) Jepson: Fl. W. Calif., 506. (1901) | (A. Gray) Jepson: Fl. W. Calif., 506. (1901) |
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