Cirsium andrewsii (A.Gray) Jeps.

Species Overview

Cirsium andrewsii, commonly called Franciscan thistle, is an uncommon thistle species. It is endemic to California, with confirmed populations along the coastline of the San Francisco Bay Area from Marin County to San Mateo County; isolated populations have also been reported in the Klamath Mountains and the Sierra Nevada.

Habitat

This thistle grows in coastal habitats including sea bluffs and canyons, and is sometimes found growing on serpentine soils.

Growth Habit

It is a biennial or perennial plant that produces an erect, leafy stem that can reach up to two meters in height.

Stem Characteristics

The stem is highly branched, dense to clumpy, fleshy, and covered in cobwebby fibers, especially when it is new.

Leaf Characteristics

Its leaves are woolly or cobwebby, spiny along the edges, and sometimes do not have lobes or deep cuts. Leaves are borne on petioles with winged, spiny margins, and some of these spines grow longer than one centimeter.

Inflorescence Structure

The inflorescence holds one or more flower heads. Each flower head can be up to 3 centimeters long by 5 centimeters wide, is wispy with cobwebby fibers, and lined with very spiny phyllaries.

Flowers

Each flower head is packed with dark purplish-pink flowers that reach up to around 2.5 centimeters in length.

Fruit Characteristics

The plant produces a fruit that is an achene, with a dark brown body about half a centimeter long and a pappus around 1.5 centimeters long.