All the tetraploid populations of annual stephanomerias are placed into Stephanomeria elata. The plants are self-compatible and are highly self-pollinating. Stephanomeria elata is an allotetraploid species that arose following hybridization between S. exigua and S. virgata (L. D. Gottlieb 1972). Substantial interpopulation morphologic variability occurs in the length, width, and color of ligules, number of florets, and degree of reflexing of bractlets of the calyculi. Two groups of populations can be distinguished. One group has large cypselae, averaging 3.9–4.5 mm, the bristle bases are widened, and about 30% of the pollen grains have four pores. The second group has smaller cypselae, averaging 2.8–3.3 mm, the bristle bases are not widened, and less than 10% of the pollen grains have four pores. The former group of populations is generally found from southwestern Oregon south to Monterey County in the Coast Ranges of California and on the western slopes of the Sierra Nevada to Fresno County. The latter group is distributed near the coast from Marin County to Santa Barbara County, California. The two groups overlap in Santa Cruz, Santa Clara, and Monterey counties; the distinctions are less evident there.
Stephanomeria elata and its parents S. exigua and S. virgata form a polyploid complex that perplexed taxonomists for many years. Once the morphologic distinctions between parental species were clarified (L. D. Gottlieb 1972), particularly, the presence versus absence of the longitudinal groove on each face of their cypselae that distinguishes S. exigua and S. elata from S. virgata, and the allotetraploidy of S. elata was recognized, it has become much simpler to distinguish the three species in the field.
Stephanomeria elata is a species of flowering plant in the family Asteraceae known by the common names Santa Barbara wirelettuce[1] and Nuttall's wirelettuce. It is native to Oregon and California, where it grows in coastal and inland mountain ranges, including the Sierra Nevada. It can be found in many types of habitat. It is an annual herb producing a slender, erect stem often exceeding one meter in maximum height. It is hairy to hairless and often glandular. The leaves are mostly located in a basal rosette, the largest reaching 10 centimeters long. Smaller, much-reduced leaves occur farther up the stem. The leaves drop early, leaving the plant naked for most of the year. Flowers occur singly or in small clusters along the stiff branches. Each head contains up to 15 or 16 ray florets, each with an elongated tube and a pink ligule 6 or 7 millimeters long. The fruit is an achene tipped with a spreading cluster of long, plumelike pappus bristles.
Stephanomeria elata is a species of flowering plant in the family Asteraceae known by the common names Santa Barbara wirelettuce and Nuttall's wirelettuce. It is native to Oregon and California, where it grows in coastal and inland mountain ranges, including the Sierra Nevada. It can be found in many types of habitat. It is an annual herb producing a slender, erect stem often exceeding one meter in maximum height. It is hairy to hairless and often glandular. The leaves are mostly located in a basal rosette, the largest reaching 10 centimeters long. Smaller, much-reduced leaves occur farther up the stem. The leaves drop early, leaving the plant naked for most of the year. Flowers occur singly or in small clusters along the stiff branches. Each head contains up to 15 or 16 ray florets, each with an elongated tube and a pink ligule 6 or 7 millimeters long. The fruit is an achene tipped with a spreading cluster of long, plumelike pappus bristles.
