210 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Ocean within the tropics ; and this concerns several of the species them- 

 selves as well as their mode of occurrence, particularly such as determine 

 the general aspect of the vegetation. The author describes 13 species 

 collected on the ' Sealark ' Expedition, one of which is new. 



Ok am uk a, K. — Icones of Japanese Algae. Tokyo : (1907) i. Nos. 1-3. 



Fungi. 



(By A. Lorrain Smith, F.L.S.) 



Experiments with Sclerospora graminicola.* — G. B. Traverso pub- 

 lished some time ago an account of a Sclerospora found on plants of 

 Setaria italica, which varied somewhat from the typical form Scl. grami- 

 nicola. Further gatherings of the fungus have enabled him to examine 

 it more carefully. He finds that the conidial forms of the two are iden- 

 tical, but all attempts to infect plants other than S. italica have failed, 

 and he has also found the fungus richly infesting S. italica in a field, 

 and leaving untouched the plants of S. viridis that grew there also in 

 abundance. Traverso considers that he is dealing with a new biological 

 form, var. Setarim-italicce.. 



Studies in North American Peronosporales. Il.f — G. West Wilson 

 discusses in this paper the two tribes Phytophthorese and Rysotheceae, 

 which normally germinate by means of zoospores. The latter includes 

 the genera Basidiophora, Sclerospora, Rhysotheca, and Pseudoperonospora. 

 Rhysotheca, a new genus, includes the greater number of species 

 usually referred to Plasmopara, the type species being Plasmopara 

 viticola. Two species are assigned to Pseudoperonospora : P. cubensis 

 and P. Geltidis. The former causes a somewhat widespread and serious 

 disease on Cucurbitacege. P. Celtidis is the only member of the order 

 which affects a tree — it grows on Celtis occidentalis,andi& somewhat rare. 



Mycotheca of the School of Pharmacy of Paris. XXI. £ - 

 O. Bainier gives a further series of interesting studies of various 

 fungi. Two additional species of Syncephalastrnm were cultivated and 

 are now described and figured ; they differ from the previously known 

 species in having stolons. Piptocephalis Freseniana was also grown and 

 the development watched ; zygospores were produced on the mycelium 

 cultivated with Mucor fragilis on a crust of bread moistened with water. 



A new species of Trichurus is described ; it resembles somewhat a 

 Stysanus, but the fructification is beset with long bristles. A new 

 genus and species of Hyphomycetes (Dematicese) Chlamydomyces diffusus 

 is described and compared with Trichocladium asperum and Acremoniella 

 utra. All three are closely related. 



Cytology of Humaria rutilans.§ — H. C. L. Fraser has made a 

 careful study of this Discomycete with a view to ascertaining the 



* Nuovo Giorn. Bot. Ital., xiv. (1907) pp. 575-8. 



+ Bull. Torrey Bot. Club, xxxiv. (1907) pp. 387-416. 



\ Bull. Soc. Mycol. France, xxiii. (1907) pp. 218-41 (4 pis.). 



§ Ann. of Bot., xxii. (1908) pp. 35-53 (2 pis.). 



