PHENETIC ANALYSIS OF MORPHOLOGICAL VARIATION IN THE LOBELIA-CARDINALIS COMPLEX (CAMPANULACEAE, LOBELIOIDEAE)

The Lobelia cardinalis complex (Campanulaceae: Lobelioideae) is a grou p of red-flowered, hummingbird-pollinated, diploid, perennial herbs th at are found in wetland habitats throughout much of North America. Clu ster analysis and principal components analysis of 66 morphological ch aracters extracted from 103 population samples failed to disclose grou ps of populations that were morphologically distinguishable and geogra phically coherent. We conclude that the complex comprises a single spe cies, L. cardinalis, and that this species cannot be divided into infr aspecific taxa. It is most closely related to L. siphilitica, a blue-f lowered bee-pollinated species with which it is partly sympatric. Repr oductive isolation of the two appears to be a function of pollinator d ifferences.