Taxonomic Note of Polysiphonia pacifica (Ceramiales, Rhodophyta) Complex with Focus on Pacific Isolates

doi:2005.20.1.15

Algae > Volume 20(1); 2005 > Article

Algae 2005;20(1): 15-23. doi: https://doi.org/10.4490/algae.2005.20.1.015

Myung Sook Kim^* and Eun Chan Yang¹

Research Institute for Basic Sciences, Pusan National University, Busan 609-735 and
¹Department of Biology, Chungnam National University, Daejon 305-764, Korea

ABSTRACT

Polysiphonia pacifica is rhodomelaceous red algal species that includes five varieties in Pacific Ocean: P. pacifica var. delicatula, P. pacifica var. distans, P. pacifica var. determinata, P. pacifica var. disticha, and P. pacifica var. gracilis. We here report morphology and phylogeny of P. pacifica to confirm the relationships among previously described varieties as a loan of type specimens from US and to assess phylogenetic relationships of closely related species using plastid protein-coding rbcL gene. Polysiphonia pacifica is distinguished by having creeping filaments attached by unicellular rhizoids not cut off by cross walls, four pericentral cells, ecorticate, trichoblasts rare, ultimate branchlets attenuate at the tip but not pungent, and tetrasporangia in long straight series in the ultimate branchlets. The protein-coding plastid rbcL gene sequence data show that P. pacifica is distinctly different from the superficially similar species, P. morrowii and P. stricta. However, the rbcL sequences of P. pacifica var. pacifica and var. disticha are identical though they have morphological variation.

Key words: Ceramiales, morphology, phylogeny, Polysiphonia pacifica, rbcL, Rhodophyta, taxonomy