Erigeron serpentinus
Encyclopedia
Erigeron serpentinus is a rare species of flowering plant in the daisy family
known by the common names serpentine fleabane and serpentine daisy. It is endemic to Sonoma County, California
, where it is known from three occurrences in and around The Cedars. There are an estimated 1100 individuals in existence. The Cedars is a canyon habitat with serpentine soil
s surrounded by non-serpentine terrain; it is home to several rare serpentine-endemic plant species. This daisy was discovered there and described to science in 1992.
It is a perennial herb producing an upright stem up to 40 or 50 centimeters long from a taproot
and caudex
unit. The linear leaves are up to 4 centimeters long and under a millimeter wide. The inflorescence
is a solitary flower head
or a cluster of up to four heads. Each has up to 13 white ray florets 7 or 8 millimeters in length which turn blue as they dry.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
known by the common names serpentine fleabane and serpentine daisy. It is endemic to Sonoma County, California
Sonoma County, California
Sonoma County, located on the northern coast of the U.S. state of California, is the largest and northernmost of the nine San Francisco Bay Area counties. Its population at the 2010 census was 483,878. Its largest city and county seat is Santa Rosa....
, where it is known from three occurrences in and around The Cedars. There are an estimated 1100 individuals in existence. The Cedars is a canyon habitat with serpentine soil
Serpentine soil
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth's mantle....
s surrounded by non-serpentine terrain; it is home to several rare serpentine-endemic plant species. This daisy was discovered there and described to science in 1992.
It is a perennial herb producing an upright stem up to 40 or 50 centimeters long from a taproot
Taproot
A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...
and caudex
Caudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
unit. The linear leaves are up to 4 centimeters long and under a millimeter wide. 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 solitary flower head
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
or a cluster of up to four heads. Each has up to 13 white ray florets 7 or 8 millimeters in length which turn blue as they dry.