Cirsium hydrophilum facts for kids
Quick facts for kids Cirsium hydrophilum |
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| Suisun thistle | |
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| Genus: |
Cirsium
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| Species: |
hydrophilum
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Cirsium hydrophilum, also known as the Suisun thistle, is a special type of thistle plant. It grows only in California, which means it is endemic to that state. You can find this thistle mainly in the San Francisco Bay Area and the Sacramento-San Joaquin River Delta. It loves to grow in very wet, boggy places.
What Does it Look Like?
The Suisun thistle can grow quite tall, up to 2 metres (6.6 ft) (about 6.5 feet). It has a stem that branches out and looks a bit like a cobweb.
Its leaves are longest near the bottom of the plant. They can be almost 90 centimetres (35 in) (about 3 feet) long! The leaves have jagged edges, like teeth, and are covered in sharp spines. These spines are especially noticeable along the petiole, which is the stalk that attaches the leaf to the stem.
Flowers and Seeds
The plant produces one or more flower heads. Each flower head is about 3 centimetres (1.2 in) (just over an inch) long. The flower heads are surrounded by sticky, twisted, and spiny leaf-like parts called phyllaries.
Inside the flower heads, you'll find pretty pink to purple flowers. After the flowers bloom, they produce a small fruit called an achene. This achene is only about 2–4 millimetres (0.079–0.157 in) long. It has a fluffy top called a pappus, which is about 1.5 centimetres (0.59 in) long. This pappus helps the seeds float away in the wind.
Different Types of Suisun Thistle
There are two very specific types, or varieties, of Cirsium hydrophilum:
- The rare Suisun thistle (Cirsium hydrophilum var. hydrophilum) is found in only two places. Both are in the Suisun Marsh, which is a salt marsh area within the Delta in Solano County. This variety is considered an endangered species by the federal government. This means it is at high risk of disappearing forever.
- The very rare Mt. Tamalpais thistle or Vasey's thistle (Cirsium hydrophilum var. vaseyi) is known from about twenty locations. These include Mount Tamalpais in Marin County, Vacaville, California in Solano County, and inside the Presidio in the City of San Francisco. This variety is not currently listed as an endangered species by federal or state governments.
