76 SUAIMARY OF CURRENT RESEARCHES RELATING TO 



previously known only from AV. Norway and England. An account of 

 thirty different associations at elevations varying from 5000 ft. to 

 2700 ft. is given. The total number of species recorded in the area is 

 500, exclusive of diatoms, but would be largely increased by a syste- 

 matic investigation of the Myxophyceaj, and by an autumn collection. 

 The author concludes that at moderate altitudes in S. Norway (not 

 exceeding 4000 ft.) almost as many alga? occur as in the lowlands, the 

 richness or poverty of the alga-flora depending largely upon the 

 geologic formations and the rain and snowfall. Many of the Desmids 

 were of distinctly western types, a few were arctic or alpine. Many are 

 rare, and two are new to science. E. S. G. 



Development of Batrachospermum moniliforme. — H. Kylin {Ber. 

 Devtsch. Bot. GeseJl, 1917, 35, 155-04, 7 figs. ; see also />W. Centralbl, 

 19 IH, 137, 152-3). An account of the nuclear division of B. monili- 

 forme in connexion with its reproduction. Various accounts of the 

 process in that genus have been put forward, and the author hopes to 

 decide wdiich is correct. His conclusions are as follows : —The sperma- 

 tangia mother-cells are not to be distinguished from the vegetative cells. 

 The young spermatangiura possesses a small nucleus, in wdiich is a 

 nucleolus surrounded by a light halo. In the ripe spermatium this halo 

 is lacking, and it appears now as if the nucleus were composed of about 

 ten granules. From this the author concludes that the nucleus of the 

 ripe spermatium goes through a later prophase condition, as in the other 

 Florideffi. Schmidle's assertion that the spermatium nucleus divides 

 after adhesion to the trichogyne was not proved with certainty. AA hetlier 

 the occurrence of two nucleus-like granules points to a true nuclear 

 division, or lias its origin merely in a dissolution of the nucleus, was not 

 determined. On the ground of other observations, however, the author 

 believes in a mitotic division. At the fusion of the two sexual nuclei 

 in the carpogonium they are in a resting stage. The spermatium 

 nucleus, however, on issuing from the spermatangium is in a later 

 prophase condition ; the male nucleus at the time of fertilization, on the 

 other hand, is in a resting stage. From this the author concludes that 

 in the interval a nuclear division took place, and he considers Schmidle's 

 view really correct. Further, he found no indication of a trichogyne 

 nucleus, though Davis records one. Past investigations seem to show 

 tl;at normally the Floridean trichogyne contains a nucleus. Thus 

 Batrachospermum forms an exception, which is explained ])y its low state 

 of development. The author then describes the first division of the 

 zygote nucleus. Nothing was observed of the prophase stages until the 

 nucleus was in the diakinesis stage of a reduction-division. If the 

 interpretation of the first phase as a heterotypic division be correct, the 

 second phase would be the homotypic, and the four cells from which 

 the gonimoblast is developed would be homologous with the four tetra- 

 spores which arise after a reduction-division. Also, the differences in 

 the development of the gonimoblast in Batrachospormum as compared 

 with that of NemaUon indicate the lower state of development of the 

 former. The spore germination is alike in both genera. Schmidle's 

 assertion that the unicellular hairs of B. moniliforme lack a nucleus is 

 incorrect. Each hair possesses a small nucleus, which is easily demon- 

 strated by iron-haematoxylin. E. S. G. 



