About Cirsium douglasii DC.
Cirsium douglasii DC., commonly known as Douglas' thistle, is a native thistle that grows as a biennial or short-lived perennial herb. It reaches up to 2.5 metres (8.2 ft) in height, and has a branching, woolly stem. The longest leaves are gray-tomentose, located near the base of the plant, and grow up to 1 metre (3.3 ft) long. These basal leaves are sometimes lobed or toothed, and are borne on a spiny petiole. Its inflorescence is a cluster of several flower heads surrounded by small leaves. Each flower head measures up to 3 centimetres (1.2 in) long, and is lined with spiny phyllaries that have purple tips. The flower head holds either purple or white flowers. The fruit is a dark-colored achene that measures 2–4.5 millimetres (0.079–0.177 in) in length/diameter, and is topped with a pappus that can reach up to 2 centimetres (0.79 in) in length. There are two recognized varieties of this species: Cirsium douglasii var. breweri (A.Gray) D.J.Keil & C.E.Turner, found in California, Oregon, and Nevada; and Cirsium douglasii var. douglasii, found in California.
