Introduction

Cedar or limestone glades (Figure 12.1) are open areas of rock pavement, gravel, flagstone, and/or shallow soil in which occur natural, long-persisting (edaphic climax) plant communities dominated by herbaceous angiosperms and/or cryptogams (J. M. Baskin and Baskin 1985a; Quarterman, Burbanck and Shure 1993). They may, or may not, be surrounded by forest (Galloway 1919). Cedar glades may support low densities of woody plants, which become established in deep soil-filled cracks in the bedrock (e.g., Picklesimer 1927 [see J. M. Baskin and Baskin 1996a]; Quarterman 1950b). The dominant plants are C4 summer annual grasses; C3 winter annual, summer annual, and/or perennial herbaceous dicots; mosses (primarily Pleurochaete squarrosa); the cyanobacterium Nostoc commune; and crustose, foliose, and fruticose lichens (Quarterman 1948, 1950a, b; Finn 1968; Mahr and Mathis 1981; Somers et al. 1986; Drew 1991; Dubois 1993)

Historically, in the Central Basin the term cedar glades has referred to rocky limestone openings (“glades”) and the adjacent redcedar–redcedar/hardwood–hardwood forest complex, that is, Quarterman's (1989) glade complex or ecosystem (e.g., Safford 1851; Galloway 1919; Freeman 1933; Quarterman 1950b; Mahr and Mathis 1981). However, in the past 20–30 years botanical studies in cedar glades of the southeastern United States (e.g., Ware 1969; J. M. Baskin and Baskin 1985a; Somers et al. 1986; Quarterman, Burbanck and Shure 1993; J. M. Baskin, Webb and Baskin 1995) have used cedar glades (or limestone glades) in reference to the rocky openings only, that is, glades or open glades, sensu Quarterman 1950b), and this is how we use the term in the present chapter.