Algae. 1990; 5(1): 51-56.

Comparative Morphology and Hybridization of Polysiphonia acuminata from California and P. japonica var. japonica from Korea

Ha-Yong Yoon, John A. West

Department of Science, Chinju Teachers College, Department of Botany, University of California

Cultured plants of the two species are quite similar in morphology especially in the formation of endogenous branches from the base of the main axes, a character previously reported only in Polysiphonia japonica. In P. acuminata the main axes are not corticated in contrast to P. japonica in which cortication arises along the older axes. Tetrasporangial and gametangial development requires about the same length of time (about 30 days) in both species. In hybridization of P. acuminata and P. japonica. carposporophytes develop slowly (about 90 days) compared with those of self-crosses (about 30 days) and are fewer in number and germinating carpospores die early in development. Comparative morphology in culture and hybridization results suggest that the two species are becoming genetically isolated.

Keywords : Rhodophyta, Polysiphonia acuminata, P. japonica, culture, hybridization, genetic isolation