''Cirsium douglasii'' is a species of

thistle Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. ...

known by the common names Douglas' thistle and California swamp thistle. It is native to the central coast and northern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

ranges, foothills, and plateaus, and adjacent parts of southern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and northwest

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

. It grows in wet places in a number of types of habitat.Calflora taxon report, University of California, ''Cirsium douglasii'' DC., Douglas' thistle, swamp thistle
/ref>

Description

This native thistle, ''Cirsium douglasii'', is a biennial or short-lived

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

herb growing up to tall, with a branching woolly stem. The longest gray-tomentose leaves, located about the base of the plant, are up to long. They are sometimes lobed or toothed and are borne on a spiny petiole.Flora of North America: ''Cirsium douglasii''
/ref> The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a cluster of several

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

surrounded by small leaves. Each flower head is up to long and lined with purple-tipped spiny phyllaries. The head contains purple or white flowers. The fruit is a dark-colored

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

long/diameter with a pappus which may reach in length. ;Varieties * ''Cirsium douglasii'' var. ''breweri'' (A.Gray) D.J.Keil & C.E.Turner -

* ''Cirsium douglasii'' var. ''douglasii'' -

References

External links

*
Jepson Manual treatment — ''Cirsium douglasii''''Cirsium douglasii'' — Calphotos Photos gallery, University of California
douglasii Flora of the Western United States Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Natural history of the San Francisco Bay Area Plants described in 1838 Flora without expected TNC conservation status {{Cynareae-stub