Alsae 



&^ 



The microphytic benthos or littoral Alga-flora of the Yan Yean 

 Reservoir was richer in species than the phytoplankton and con 

 tained many interesting types. Many species common to the plankton 

 and the benthos attain first a maximum in the plankton and sub- 

 sequently a maximum in the benthos, the time which elapses between 

 these two maxima varying from three to eight weeks. 



Some light is thrown on the origin of the microphytic benthos 

 and of the phytoplankton by the investigations carried out in other 

 parts of the drainage area. The upper dams yield few plankton 

 species owing to the disturbed State of the water, but their exami- 

 nation indicates that the Yan Yean Reservoir does not derive its 

 numerous algal constituents from these dams although receiving six- 

 sevenths of its water-supph^ from them. The rieh Alga-flora of the 

 Yan Yean appears to be derived almost entirely from its own small 

 catchment basin. The phytoplankton is partially recruited from the 

 microphytic benthos, and it also consists in part of well-established 

 forms which are not recruited from the shore-regions. Some of these 

 well-established plankton forms seemingly supply the benthos with 

 recruits in greater or smaller numbers during the autumnal fall 

 of temperature. 



Over 300 species of Algae were observed in the complete col- 

 lections from the entire Yan Yean drainage area. Of these, 14 species 

 and 11 varieties are here described for the first time, and 4 species 

 and 5 varieties which had previously been only partially described 

 are here dealt with in greater detail, and for the first time figured. 



The paper is illustrated by six plates and ten text-figures. Tables 

 of the phytoplankton and of the littoral flora shew the relative fre- 

 quency of each species. E. S. Gepp. 



West, W. and G. S. West. A Monograph of the British De- 

 sniidiaceae. Vol. III. (London: Ray Society. XV, 247 pp. Plates 

 65—95, partly coloured. 1908.) 



In this, the third volume of their monograph, the authors include 

 füll descriptions of 174 species of Cosmarüim, with varieties, S3'no- 

 nyms, literature, distribution, and critical notes. Keys to the species 

 are provided; and an additional list of bibliography is appended. 

 Two new species are described , C. didynioprotiisum , C. entocJioti- 

 drum, and eleven new varieties and three new .forms. Each plate 

 contains several figures, thus permitting every species, variety and 

 form to be illustrated. E. S. Gepp. 



West, W. and G. S. West. Fresh-water Algae from Burma, 

 including a few from Bengal and Madras. (Ann. Roy. Bot. 

 Gard. Calcutta. Vol. VI, part IL Calcutta, p. 175—260, with seven 

 plates. 1907.) 



These algae were collected by I. H. Burkill in 1904 mostly in 

 Burma and partly in Bengal and Madras. The number of genera 

 comprised is 71, with 276 species and 16 varieties. New to science 

 are the two genera — Euastridiiim and BurküUa — and the foUowing 

 spiecies: Microthaninion curvatum, Vaiicheria orientalis, V . globidifeva , 

 Spirogyra exilis, S. ovientalis, Moiigeotia producta, Closteniim substri- 

 gosiiin, Enastvum bhamense, Enastridium Prainii, Cosniarimn Prainii, 

 C. glaphyronotiim , C. quadriverriicosum , C. trwerrucosum , C. Biirkillii, 

 C. mansangense, Xnnthidium Biirkillii, X. sexmaniillatiini, ArtJiro- 

 desmiis fusijorniis, Staurastriini Prainii, S. disparatum, S. niansaii- 



