Porphyra tanegashimensis, a New Species of Rodophyceae from Tanegashima Island in Southern Japan

Since September 1971, the present writer has been studying the genus Porphyra in the north-eastern coast of Tanegashima Island, Kagoshima Prefecture, and of these species of Porphyra, one is ascertained to be a new species. In the present paper, Porphyra tanegashimensis sp. nov. is proposed and discussed in comparison with some other related species of Porphyra. The main morphological and ecological characters of this new species are as follows:1) The present plants are found during all seasons of the year in the form of leaf-like fronds, and well grown ones, reaching 10-15 cm in height, though chiefly found from September to November. The most noticeable characteristic of these plants is that the fronds issue many linear lateral branches.2) Sexual reproductive organs are found from late September to early April.3) Monosporangia are formed at the upper marginal part of the frond through all seasons, and the monospores are mostly liberated from March to September.4) Both germinating monospore and conchospore grow into similar plants with the lateral branches mentioned above.5) The adequate water temperatures for growth of the plants are recognized to be higher by 3-5°C than those for some other species of the cultivated Porphyra.