- Cirsium douglasii
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Cirsium douglasii Scientific classification Kingdom: Plantae (unranked): Angiosperms (unranked): Eudicots (unranked): Asterids Order: Asterales Family: Asteraceae Tribe: Cynareae Genus: Cirsium Species: C. douglasii Binomial name Cirsium douglasii
DC.Cirsium douglasii is a species of thistle known by the common names Douglas' thistle and California swamp thistle. It is native to the central coast and northern California ranges, foothills, and plateaus, and adjacent parts of southern Oregon and northwest Nevada. It grows in wet places in a number of types of habitat.
Description
This native thistle, Cirsium douglasii, is a biennial or short-lived perennial herb growing up to 2.5 metres (8.2 ft) tall, with a branching woolly stem. The longest gray-tomentose leaves, located about the base of the plant, are up to 1 metre (3.3 ft) long. They are sometimes lobed or toothed and are borne on a spiny petiole.
The inflorescence is a cluster of several flower heads surrounded by small leaves. Each flower head is up to 3 centimetres (1.2 in) long and lined with purple-tipped spiny phyllaries. The head contains purple or white flowers. The fruit is a dark-colored achene 2–4.5 millimetres (0.079–0.18 in) long/diameter with a pappus which may reach 2 centimetres (0.79 in) in length.
External links and references
- Jepson Manual treatment — Cirsium douglasii
- USDA Plants Profile: Cirsium douglasii
- Flora of North America: Cirsium douglasii
- Cirsium douglasii — U.C. Photo gallery
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