西沙群岛凹顶藻属的分类研究

凹顶藻属(Laurencia)属于红藻门,真红藻纲,仙菜目,松节藻科,凹顶藻亚科。本属是松节藻科种类最多的少数几个属之一，目前世界上已知约85种左右,多生于热带、亚热带和温带海域。本属的种类变异很大,在分类上被认为是很困难的一个属。 本文对我国西沙群岛产的凹顶藻属进行了分类研究,除因标本数量过少或因缺乏必要的生殖器官,有待将来调查采集补充标本后再行研究外,经鉴定共有下列11种,隶于两个亚属和6个组。

STUDIES ON THE GENUS LAURENCIA OF THE XISHA ISLANDS, GUANGDONG PROVINCE. CHINA

Marine algae from the Xisha Islands, Guangdong Province, China collected by the members of the Institute of Oceanology(1957, 1958, 1975 and 1976)have been studied and some results published in a series of papers commencing in 1975. During the course of the study eleven species belonging to six sections and two subgenus are found, of which five species, namely Laurencia decumbens Kuetz. L. galtsoffi Howe, L. mariannensis Yam L. pinnata Yam, and L. cartilaginea Yam. are newly recorded here for China. Laurencia articulata Tseng from Hong Kong is founded on sterile specimens. According to Tseng(1943), it belonged to Section Forsterianae. On re-examining it, we found that in its longitudinal section of the stichidium, the sporangia are arranged at right angles to the central axis (fig. 9).According to Saito (1967), this species ought to belong to the Subgenus II Chondrophycus and Section Chondrophycus. Yamada (1931) regarded lenticular thickenings as a diagnostic character at the sectional level and distinguished the Section Forsterianae from the Section Laurencia of the Subgenus I Laurencia on the basis of the presence of lenticular thickening in the walls of the medulla. We are of the opinion that this characteristic should also have section bearing in the Subgenus II Chondrophycus and, therefore propose to establish a new section for L. articulata and L. verticillata as follows: