Stigma Types in Bromeliaceae-A Systematic Survey

Abstract

Over 400 taxa in the Bromeliaceae were surveyed for stigma morphology. Five mor- phological categories (conduplicate-spiral, simple-erect, cupulate, convolute-blade, and coralliform) account for all known variation in bromeliad stigma morphology. The coralliform type is described and illustrated for the first time. The subfamilies Bromelioideae and Pitcairnioideae appear to be nearly homogeneous for the conduplicate-spiral stigma type. All five of the stigma types are found in the third subfamily, Tillandsioideae, where stigma variability promises to be the most useful systematically. There appear to be correlations between the simple-erect stigma type and 1) derived sexual systems (i.e., dioecism, andromonoecism, cleistogamy) within the family, and 2) xeric- epiphytism in the genus Tillandsia. In conjunction with other floral features, stigma morphology may be 'useful in refining generic and infrageneric circumscriptions. In an earlier paper (Brown and Gilmartin 1984) we described the morphological characteristics of three stigma architectural types then en- countered in 17 taxa of the Bromeliaceae. Utley (1978, 1983) has provided a description and drawing of a fourth architectural form. The four morphological types have been designated sim- ple-erect, conduplicate-spiral, convolute-blade,