DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH-AMERICA .7. SECTION HYBRIDA

Five North American populations were compared with four type specimens referable to section Hybrida using multivariate morphometrics and image analysis. From this study, two species in the section are recognized worldwide: B. abilii Reis and B. virgato-decaisneanum Sirodot (syn. B. mikrogyne Flint et Skuja in Flint and B. virgato-decaisneanum var. cochleophilum Teodoresco). The two species are distinguished on the basis of significantly different whorl sizes (diameter: ($) over bar x = 759 vs. 349 mu m and fascicle length: ($) over bar x = 16.0 vs. 7.4 cells, respectively). In addition, B. abilii has ovoid, compressed whorls with little secondary fascicle development whereas B, virgato-decaisneanum has obovoid, separated whorls with secondary fascicles. Only B. virgato-decaisneamum is found in North America, ranging from southern Ontario in the north to Louisiana in the south. Discussion of and a synoptic key to the sections of Batrachospermum with axial carposporophytes are provided.