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Cirsium douglasii
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Douglas' Thistle
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Cirsium douglasii

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About Douglas' Thistle (Cirsium douglasii) 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. 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. 177 in) long/diameter with a pappus which may reach 2 centimetres (0. 79 in) in length. VarietiesCirsium douglasii var. breweri (A. Gray) D. J. Keil & C. E. Turner - California, Oregon, NevadaCirsium douglasii var. douglasii - California
Plant Description
Plant Type
Perennial herb

Max. Height
6.6 - 16.4 ft (2 - 5 m)

Flower Color
Pink, Purple

Native Status

Natural Setting
Elevation ?
23' - 10161'

Annual Precip. ?
11.7" - 137.4"

Summer Precip. ?
0.26" - 4.08"

Coldest Month ?
27.9° F - 49.9° F

Hottest Month ?
49.0° F - 74.4° F

Humidity ?
0.03 vpd - 23.44 vpd

Landscaping Information
Common uses
Butterfly Gardens

Nursery Availability
Never or Almost Never Available

Other Names
Common Names
California Swamp Thistle

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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