DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH-AMERICA .8A. SECTION BATRACHOSPERMUM, BATRACHOSPERMUM-GELATINOSUM

Eighty-six populations of Batrachospermum gelatinosum were examined fr om throughout its known range in North America and were compared using multivariate morphometrics and image analysis. Morphological variabil ity was as great in individual populations as that measured among loca tions. Populations pooled for each biome showed a north-south trend in whorl and carpogonium size. The mean measurements for the tundra were significantly smaller in whorl diameter and larger in carpogonium siz e than those for the coastal plain. B. gelatinosum is widely distribut ed in North America, having been collected from the north slope of Ala ska and Baffin Island in the north to Texas and Louisiana in the south . In addition to the populations analysed, herbarium specimens from No rth America were examined and confirmed locations in 17 US states, fou r Canadian provinces and the Yukon territory were added. Three populat ions, two from the boreal forest (Newfoundland) and one from the decid uous forest (Rhode Island), were examined for morphological variation throughout the growing season. The two Newfoundland populations were o bserved year-round, whereas the Rhode Island population was present on ly from October to June. Carposporophyte diameter showed a spring maxi mum in all three populations. In addition, there were seasonal trends in whorl diameter, carposporophytes per whorl and carpogonium length i n the Rhode Island population.