Cirsium cymosum
Encyclopedia
Cirsium cymosum is a species of thistle
known by the common name peregrine thistle. It is native to California
, where it grows in several types of mountain and foothill habitat, and its range extends just into Oregon
. This native thistle is a biennial or perennial herb with a maximum height just over a meter. It is coated in soft and coarse hairs and sometimes cobwebby fibers. The spiny leaves may reach 30 to 50 centimeters long, especially toward the base of the stem. They are deeply cut into lobes which are lined with sharp teeth. The inflorescence
is a cluster of flower heads
each up to 3 centimeters long and 5 wide. The head is lined with sticky, spiny phyllaries
and filled with dull white flowers. The fruit is an achene
with a dark-colored body just under a centimeter long and a pappus
of hairs up to 2.5 centimeters in length.
Cirsium canovirens, the graygreen thistle, is sometimes treated as a variety of this species.
Cirsium
Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more accurately known as Plume thistles. These differ from other thistle genera in having feathered hairs to their achenes...
known by the common name peregrine thistle. It is native to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it grows in several types of mountain and foothill habitat, and its range extends just into Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. This native thistle is a biennial or perennial herb with a maximum height just over a meter. It is coated in soft and coarse hairs and sometimes cobwebby fibers. The spiny leaves may reach 30 to 50 centimeters long, especially toward the base of the stem. They are deeply cut into lobes which are lined with sharp teeth. The inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a cluster of flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
each up to 3 centimeters long and 5 wide. The head is lined with sticky, spiny phyllaries
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
and filled with dull white flowers. The fruit is an achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
with a dark-colored body just under a centimeter long and a pappus
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
of hairs up to 2.5 centimeters in length.
Cirsium canovirens, the graygreen thistle, is sometimes treated as a variety of this species.