Franciscan Thistle

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).

Biennials (or short–lived monocarpic perennials), 60–200 cm; taprooted. Stems several, erect to spreading, thinly arachnoid, soon glabrous; branches ± fleshy, usually much branched proximally, spreading to ascending. Leaves: 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. Heads several–many, in congested corymbiform arrays. Peduncles 0–7 cm. Involucres ovoid to hemispheric or campanulate, 1.5–3 × 1.5–5 cm, sparsely to densely arachnoid, finely short-ciliate. Phyllaries 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. Corollas dark reddish purple, 17–24 mm, tubes 8–11 mm, throats 3.5–6 mm, lobes 5–7 mm; style tips 3–4 mm. Cypselae dark brown, 4–5 mm, apical collars narrow; pappi 15 mm. 2n = 32.

Cnicus andrewsii A. Gray, Proc. Amer. Acad. Arts 10: 45. 1874

Cirsium andrewsii is an uncommon species of thistle known by the common name Franciscan thistle. It is endemic to California, where it is known from the coastline of the San Francisco Bay Area from Marin to San Mateo Counties. There are also reports of isolated populations in the Klamath Mountains and in the Sierra Nevada.

Cirsium andrewsii grows in coastal habitats such as sea bluffs and canyons, and is sometimes found on serpentine soils. The species is biennial to perennial, producing an erect, leafy stem which can reach two meters in height. It is highly branched, dense to clumpy, fleshy, and cobwebby with fibers, especially when new. The leaves are woolly or cobwebby, spiny along the edges, and sometimes lack lobes or deep cuts. They are borne on petioles with winged, spiny margins, some spines exceeding a centimeter in length. The inflorescence produces one or more flower heads, each up to 3 centimeters long by 5 wide, wispy with cobwebby fibers, and lined with very spiny phyllaries. The flower head is packed with dark purplish-pink flowers up to about 2.5 centimeters in length. The fruit is an achene with a dark brown body about half a centimeter long and a pappus about 1.5 centimeters long.