Systematics and biogeography of the freshwater red algal genus Batrachospermum section Batrachospermun in North America

Vis, Morgan LeFay (1995) Systematics and biogeography of the freshwater red algal genus Batrachospermum section Batrachospermun in North America. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Type and historically important specimens of 46 species and infraspecific taxa from Batrachospermum sect. Batrachosnermum were examined using multivariate morphometries and image analysis. Nine species from the cluster analysis and one other species arc recognised: B. anatinum. B. arcuatum. B. borvanum. B. carpocontorlum. B. confusum. B. fluilans. B. uelatinosum. B. heterocorticum. B. pulchrum and B. skuiae. The taxa are separated on the basis of monoecious or dioecious lhalli, carpogonium size and the presence of (1) spermatangia on the involucral filaments, (2) irregular cortication, (3) monosporangia, (4) well-curled fascicles and (5) secondary fascicles. -- Five new species are described from North America. Batrachospermum spcrmatoinvolucrum sp. nov. is distinguished by the combination of spermatangia on the involucral filaments ofthe carpogonial branch, relatively long carpogonia and regular cortical cells. B. trichofurcatum sp. nov. has unique forked trichogynes. The distinguishing feature of B. carpoinvolucrum sp. nov. is carpogonial branches with involucral filaments having apical carpogonia. B. involutum sp. nov. is distinct in having involute fascicle tips, spermatangia on one-celled involucral filaments and rhizoidal outgrowths from mid-fascicle cells. B. trichocontortum sp. nov. is named for the twisted appearance of the trichogyne tip and has rhizoidal outgrowths from mid-fascicle cells. -- North American populations of seven previously described species were examined and compared to appropriate type specimens. Batrachospermum borvanum was the most abundant and widespread species, being collected in 34 stream sites. The other six species, B. anatinunu B. areuatum. B. confusum. B. hcterocorticum. B. pulchrum and B. skuiac were present in six or fewer streams. No new populations were found of B. carpocontortum which was first described from Washington state. -- Eighty-six populations of Batrachospermum gclatinosum were examined from throughout its known range in North America. Pooled populations for each biome showed a north-south trend towards smaller whorl size and larger carpogonium size, fi- uelatinosum has been collected from the north slope of Alaska and Baffin Island to Texas and Louisiana. Three populations were examined for morphological variation throughout the growing season. Carposporophytc diameter showed a spring maximum in all three populations. There were seasonal trends in whorl diameter, carposporophytes per whorl and carpogonium length in one population.

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