Varietal transfers in Cupressus and Chamaecyparis.

Abstract

In a comprehensive monograph of the New World species of Cupressus based on studies of wild and cultivated plants, Wolf (1948) accepted 15 species (12 in the United States), one with two subspecies. Two species and one subspecies were proposed as new. Discussing the specific concepts, Wolf (1948) agreed with W. L. Jepson that the species rest on rather insecure morphological features. His key to species illustrated the scarcity of well-defined qualitative morphological characters. Many characters used, such as color of foliage, size of parts, and bark, would not be of specific value in related genera. As Wolf observed, there has been confusion in taxonomie literature of Cupressus and disagreements on ranks and synonymy. And the same author has changed his concepts. Wolf concluded that this very old group of species once occupied larger areas but in later times, etiher through climatic changes, diseases, or competition, had been reduced to the present minor role in the vegetation. The range of each species is discontinuous, consisting usually of a few isolated groves or stations which can be counted. Twisselman (1962) has suggested that C. nevadensis Abrams, of Kern Co., California, is a remnant of a once widespread complex in the arid woodland occurring across the Mojave Desert until late Pliocene. This species has been progressively restricted by increasing aridity and associated factors and now survives precariously. He noted that C. mohavensis Axelrod (Carnegie Inst. Wash. Pub. 516:86. 1939), a Miocene species related to C. arizonica , was found nearby. It seemed tenable that geographic isolation could account for the differences between C. nevadensis , С. arizonica , С. forbesii, and С. montana. Earlier, Sargent (1926) described and figured for the United States six species and one variety of Cupressus. My conservative compilation accepted six species without varieties (Little, 1953), to which should be added C. sargentii Jeps., of California, and the five varieties below. The other New World species, C. lusitanica mill. (C. benthamii Endl., C. lindleyi Klotzch), is native from Mexico to Honduras.