Cirsium douglasii

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.
Synonyms[1]

Cirsium douglasii is a species of thistle known by the common names Douglas' thistle and California swamp thistle.[2][3]

It is native to the central coast and northern California ranges, foothills, and plateaus, and adjacent parts of southern Oregon and northwest Nevada.[4] It grows in wet places in a number of types of habitat.[5]

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.[6]

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.[6]

Varieties[1]

References

  1. 1 2 The Plant List, Cirsium douglasii DC.
  2. ↑ "Cirsium douglasii_EOL".
  3. ↑ "Calflora_genus: Cirsium".
  4. ↑ Biota of North America Program 2014 county distribution map
  5. ↑ Calflora taxon report, University of California, Cirsium douglasii DC., Douglas' thistle, swamp thistle
  6. 1 2 Flora of North America: Cirsium douglasii


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