66 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the young plant is free or attached. Air-bubbles are often found in 

 connection with the floating individuals, probably formed from the 

 plant itself. The author shows that though the first cap of the young 

 plant may be, and often is, thrown off, this is by no means the rule. In 

 certain plants there is an abnormal zoospore formation, in which the 

 zoospores are either not liberated at all, or they only exhibit a very 

 sluggish movement. In the latter case, the germinating zoospore pro- 

 duces very strange forms of young plant. 



Vegetative Reproduction of Dasya elegans.* — F. Tobler describes 

 the result of experiments made by himself on the growth of Dasya 

 elegans under various conditions of light. Certain plants of this species 

 were cultivated in a vessel close to a window, with the result that after 

 two days the thallus had shed all the penicilli, as well as the smaller 

 branches, which were lying at the bottom of the glass vessel. These 

 fallen branches were seen to sprout, and the author describes and figures 

 the various stages of the process. He was able to compare with this 

 form of reproduction the normal growth of a plant from tetraspores, 

 since the cultures were carried on simultaneously. The power of re- 

 production from vegetative cells is not confined to the monosiphonous 

 portions of the thallus, but was also observed among cells which formed 

 the cortex of the polysiphonous axis. Various stages of growth are 

 figured. 



New Genus of Delesseriacese.f — F. Heydrich creates a new genus 

 Implicaria for the reception of a species /. reticulata from Loochoo, 

 Japan. The specimen described exists in the Berlin Herbarium, and in 

 certain points resembles Vanvoorstia and Glaudea, with which the author 

 compares it. He also gives the points of resemblance and difference 

 between his plant and Holmesia capensis. 



Spiral Arrangement in Florideae.J — S. Schwendener criticises ad- 

 versely the views held by Falkenberg and Rosenvinge on this subject. 

 The author states that his own experience leads him to disbelieve in the 

 continuous spiral with constant divergence in Polysiphonia, and states 

 the reasons for his scepticism. 



Caloglossa Leprieurii.§ — Marshall A. Howe publishes some remarks 

 on this species, which occurs in North and South America, as well as in 

 other parts of the world. He gives the views of authors on the question 

 of the migration into fresh water of several species of Caloglossa. 



Catalogue of British Marine Algae. || — E. A. L. Batters publishes 

 a complete list of all the British marine algas, together with the localities 

 where each species and variety occurs in the British Isles. The number 

 of genera is 259, including five of doubtful affinity. The nomenclature 

 followed is that adopted by all algologists on the Continent and in 

 America. This catalogue is as complete as it is possible to make it, 



* Ber. Deutseh. Bot. Gesell., xx. (1902) pp. 357-65 (1 pi.). 



t Tom. cit., pp. 479-83 (1 pi.). 



X Tom. cit., pp. 471-5. § Torreya, ii. (1902) pp. 149-52. 



|| Journ. Bot., xl. (1902) Supplement, pp. 1-107. 



