Factors Influencing Seed Imbibition of Blackbrush (Coleogyne Ramosissima: Rosaceae) (Notes) (Report‪)‬

Blackbrush (Coleogyne ramosissima) is a roseaceous shrub that often is dominant on shallow soils in the transitional zone between the North American warm Mojave and cold Great Basin deserts (Bowns, 1973; Bowns and West, 1976; Meyer and Pendleton, 2005). In southern Nevada, shrublands of C. ramosissima are ca. 970-1,870 m above sea level. These shrublands are floristically simple, with a closely spaced matrix of C. ramosissima and a scattered distribution of other species of shrubs (Bowns, 1973; Lei, 1995, 1997; Lei and Walker, 1997a, 1997 b). Coleogyne ramosissima is a mast-seeding species, producing abundant crops ofseeds at intervals of a few to several years, even when years of favorable winter moisture and subsequent vegetative growth occur frequently (Pendleton and Meyer, 2004). This species exhibits intraspecific variation in dormancy, germination, and emergence phenology of seeds (Lei, 1997; Pendleton and Meyer, 2004; Meyer and Pendleton, 2005). Such variation often is interpreted as a response to habitat-specific selection (Pendleton and Meyer, 2004).