A MOLECULAR AND MORPHOLOGICAL INVESTIGATION OF THE RELATIONSHIP BETWEEN BATRACHOSPERMUM-SPERMATOINVOLUCRUM AND BATRACHOSPERMUM-GELATINASUM (BATRACHOSPERMALES, RHODOPHYTA)

Four populations of the newly described freshwater red algal species B atrachospermum spermatoinvolucrum were sampled from British Columbia o n the west coast of North America and Labrador on the east. The rDNA i nternal transcribed spacer (ITS) 1 and 2 sequences, RUBISCO large subu nit (rbcL) gene data for three of the populations and morphometric cha racteristics were compared with those of B. gelatinosum. In addition, the key feature distinguishing B. spermatoinvolucrum, spermatangia on the involucral filaments of the carpogonial branch, was investigated s easonally in one British Columbia population of this species. The ITS analysis suggested that the B. spermatoinvolucrum populations were mor e closely related to particular B. gelatinosum populations than to eac h other and did not form a monophyletic clade. Two populations of B. s permatoinvolucrum from Labrador and British Columbia had identical rbc L sequences that were distinct from that of B. gelatinosum. However, t he rbcL sequence from the third population of B. spermatoinvolucrum di ffered by only one nucleotide substitution from the B. gelatinosum pop ulations. The tree generated from the morphometric data showed two gro upings, each containing populations of both taxa. The presence of sper matangia-bearing involucral filaments was a stable character throughou t the year. On the basis of these findings, B. spermatoinvolucrum is r educed to a form of B. gelatinosum. This form would encompass variant populations with characteristic carpogonial involucral filaments beari ng spermatangia.