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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
from FNA
CA
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
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 Asteraceae > tribe Cardueae > Cirsium Asteraceae > tribe Cardueae > Cirsium
Sibling taxa
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. 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. 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
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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