Cirsium loncholepis
Encyclopedia
Cirsium loncholepis is a rare species of thistle
known by the common name La Graciosa thistle. It is endemic to California
, where it is known from about 15 remaining occurrences in wetland
s where southwestern San Luis Obispo County
borders northwestern Santa Barbara County
. It grows in coastal scrub and sand dunes
, marsh
es, and moist grasslands in the watersheds
of local rivers, including the Santa Maria River. It is a federally listed endangered species
.
This native thistle may exceed a meter in height and sometimes forms a mound with fleshy, ridged stem branches. The leaves are deeply cut into lobes, toothed and wavy along the edges, the lowest leaves approaching 30 centimeters in length. The inflorescence
is a tight cluster of flower heads
, each up to 3 or 4 centimeters long. The flower head is lined with spiny phyllaries
and filled with purple-tinted white flowers with purple anthers. The fruit is a compressed achene
a few millimeters long topped with a pappus
which may be 2.5 centimeters in length.
The conservation status of this population of thistles may be reevaluated as taxonomy
studies suggest they may be members of the more common species Cirsium scariosum
.
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 La Graciosa thistle. It is endemic 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 is known from about 15 remaining occurrences in wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s where southwestern San Luis Obispo County
San Luis Obispo County, California
San Luis Obispo County is a county located along the Pacific Ocean in the Central Coast of the U.S. state of California, between Los Angeles and the San Francisco Bay Area. As of the 2010 census its population was 269,637, up from 246,681 at the 2000 census...
borders northwestern Santa Barbara County
Santa Barbara County, California
Santa Barbara County is a county located in the southern portion of the U.S. state of California, on the Pacific coast. As of 2010 the county had a population of 423,895. The county seat is Santa Barbara and the largest city is Santa Maria.-History:...
. It grows in coastal scrub and sand dunes
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
, marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
es, and moist grasslands in the watersheds
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
of local rivers, including the Santa Maria River. It is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
This native thistle may exceed a meter in height and sometimes forms a mound with fleshy, ridged stem branches. The leaves are deeply cut into lobes, toothed and wavy along the edges, the lowest leaves approaching 30 centimeters in length. 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 tight 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 or 4 centimeters long. The flower head is lined with 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 purple-tinted white flowers with purple anthers. The fruit is a compressed achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
a few millimeters long topped with 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...
which may be 2.5 centimeters in length.
The conservation status of this population of thistles may be reevaluated as taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
studies suggest they may be members of the more common species Cirsium scariosum
Cirsium scariosum
Cirsium scariosum is a species of thistle known by the common names meadow thistle and elk thistle. It is native to much of western North America from Canada to Mexico, where it grows in a variety of habitat types. This is a variable species made up of several geographic races, most of which have...
.