466 SUMMARY OF CURRENT RESEARCHES RELATING TO 



action of gravity. A local wound diverts the currents, and these 

 endeavour to repair the injury. By judicious crushing, the formation 

 of a transverse wall can be induced. Rootlets and rhizomes originate at 

 points of junction of the white currents, the rootlets arising on the dark 

 side, the rhizomes and leaves in the light. The leaves appear to arise 

 independently of the meristem-current. 



Zygospores of Desmids.* — J. A. Cushman describes and figures the 

 zygospores of thirteen species and varieties of New England desmids. 

 Two of these are new species, Cosmarium pseudo-orbiculatum and 

 Sphcerozosma reading ensis, and three of them are new varieties. The 

 author remarks on the necessity for further work on the various stages 

 in the formation of zygospores, and the possibility that such a study 

 may throw light on the validity of one or other of the two classifications, 

 one based on form alone, the other on arrangement of cell-contents. 

 The question also remains to be solved whether or not the zygospores of 

 a single species are always constant in their characters. 



Diatoms of the Orba.f — E. Morteo enumerates a list of forty-one 

 diatoms collected in six samples taken during December 1904 and 

 January 1905, from the Orba torrent between Casalcermelli and Porta- 

 nuova. He found a peculiar form of Pinnularia mesohpta, which he 

 thinks may be new. Specimens of Synedra were specially numerous. 



Trochiscia moniliformis.^ — A. M. Edwards has examined this alga 

 in its various stages of growth, and finds that the species has been 

 described and figured by various authors under as many as twenty-nine 

 different names. It occurs as a fossil as well as in a living state, and 

 has been recorded from many parts of the world. In growth it resembles 

 Hyalodlscus, while in spore-formation it resembles Melosira. 



Algse of the Weser Districts — J. Suhr begins a list of the algae of 

 the eastern hill district of the Weser, an area of about 1900 square 

 kilometres, and one of the largest stretches of woodland country in 

 Germany. The highest point is 517 m. In the present paper five species 

 of Peridinese are enumerated, and twenty-three Desmidiaceae, with the 

 localities where each occurs. As regards systematic method, the author 

 follows De Toni in the main, and for Cyanophyceae, Gomont, Bornet, 

 and Flahault. He describes his methods of preparation and examina- 

 tion of the samples collected, and gives a list of literature. 



Fresh-water Algae of East Greenland. || — E. Larsen has worked 

 out the collections made by Kruuse and Hartz on the East Greenland 

 Expedition, and by Kruuse in the Angmagsalik district. The author 

 finds 125 Chlorophyceae, of which 47 species are new to Greenland, and 

 1 Phaeosporea. The fresh-water algae of East Greenland number at the 

 present time 188, of which 150 are Desmidiaceae. Two new species and 



* Bull. Torrey Bot. Club, xxxii. (1905) pp. 223-29(2 pis.). 



+ Malpighia, xix. (1905) pp. 117-20. 



J Nuov. Notar. xvi. (1905) pp. 54-8. 



§ Hedwigia, xliv (1905) pp. 230-40. 



|| Meddel. GrSnland, xxx. (1904) pp. 77-110 (10 figs, in text). 



