Studies of the Salix lucida and Salix reticulata complexes in North America

Abstract

A study of morphological variation in the Salix lucida complex revealed three geographical races: one in northeastern North America, a second in western North America extending from Alaska to California, and a third in the southern Rocky Mountains, S. lucida ssp. lucida, Salix lucida ssp. lasiandra comb, nov., and Salix lucida ssp. caudata comb, nov., respectively. The Salix reticulata complex in the Rocky Mountain region is represented by two geographical races, ssp. reticulata in the north and ssp. nivalis in the south. Variation in ssp. nivalis suggests that hybridization and introgression occur where the two races overlap, and that the results of past hybridization are still evident in the southern Rocky Mountains.