RAPD marker variation in Eriastrum densifolium (Polemoniaceae): Implications for subspecific delimitation and conservation

Eriastrum densifolium is a perennial sub-shrub exhibiting complex morphological variation. Five subspecies are recognized, differentiated by flower dimensions and geographic/elevational distribution, One subspecies, E. d. subsp. sanctorum, is known from a single population and is recognized as a federally endangered taxon. The subspecies are difficult to distinguish and do not adequately represent the total morphological diversity in the species. Variation in the species is examined with Random Amplified Polymorphic DNA markers in an attempt to identify genetically cohesive groups of populations. Random Amplified Polymorphic DNA marker diversity indicates that genetic variation is not partitioned geographically or elevationally in the species, but genetic distance and geographic distance are well correlated. Furthermore, population relationships suggest that the currently recognized subspecies are not natural groups. Eriastrum densifolium subsp. sanctorum possesses relatively low genetic diversity in comparison to close geographic neighbors, is not genetically divergent from other populations, and is not a member of a distinct population group. In general, geographic variation indifferent Random Amplified Polymorphic DNA markers is discordant, and the resulting pattern suggests a continuum of neutral genetic marker variation in Eriastrum densifolium, with no intraspecific taxa evident.