Arenaria Lanuginosa ( Caryophyllaceae ) , Taxonomic Status and Distribution

The geographic and morphological parameters of the widespread Arenaria lanuginosa are explored with the conclusion that in North America the species consists of two, largely allopatric, intergrading varieties: A. l. var. saxosa of the southwestern USA and northwestern Mexico, and A. l. var. lanuginosa of southern Mexico and Central America, extending into South America, where it is widespread, the Caribbean Islands, and the southeastern USA (perhaps introduced). Leaf forms occur in both taxa, these often treated as distinct populational taxa. Additionally, the taxonomic reality of A. gypsostrata, related to the A. lanuginosa complex, is reconfirmed.