The common name “fleabane” was originally applied to a European species of Erigeron. Bunches of the plant hung in the house would drive out fleas. Several North American species, belonging to both the genus Erigeron and other genera, are colloquially known as fleabanes. The fact that many plants have the same common name does cause confusion.
The pictured “fleabane” is Erigeron inornatus, also commonly known as California rayless fleabane. Among other names for this plant are fleabane daisy and rayless fleabane.
California rayless fleabane is a native member of the Aster Family that grows in dry, often rocky areas of California, Washington, Nevada and Oregon.
A perennial, California rayless fleabane has a stout taproot and a root crown. The alternate, linear leaves are gradually reduced in size upward on the stem. An inflorescence of 1 to 15 flower is at the end of the stem. Rayless fleabane flowers are composed entirely of yellow disk flowers. An involucre of vertically overlapping yellow green, linear phyllaries (bracts) surrounds the disk flowers. The fruit is an achene topped by a pappus of barbed bristles.
Erigeron comes from the Greek “eri” meaning spring and “geron” meaning an old man, perhaps in reference to the hairy, white pappi.
These California rayless fleabane plants were photographed in June along the Falls Loop Trail at Burney Falls State Park (CA).