ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 187 



Fungi. 



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



Study of Rhizopus.* — Jim Haiizawa has made cultures and com- 

 parative studies of a number of species of this genus, which he classifies 

 in three groups : — (1) The nigricans-gvonip, with rather large sporangia 

 and spores ; (2) the nodosKS-gYowi^, altogether smaller ; and (::>) the 

 ori/zde-grou-p, of which the species are thermophilous. He lists the 

 species under each of these groups, and gives a kev to their determination. 



Spore-germination and Infection with Plasmopara viticola.t — 

 This subject has been studied by C. T. Gregory. He was successful in 

 following the germination of the oospores. They produce a promycelium 

 terminating in a conidium; which again germinates, forming zoospores ; 

 these latter infect the host-plant. The zoospores or swarmspores pene- 

 trate the leaf by the stomata of the under surface. A detailed account 

 of the germination of the spores is given by the writer. 



Genus Keithia.| — E. J. Durand gives an account of the three 

 species comprised in Keithia. They are all parasites of coniferous 

 leaves, and the genus is allied to Fhacidmm^ from which the first species, 

 Keithia (Fhacidinm) tetraspora was withdrawn on account of the septate 

 spores. In all the species there are only two to four ohve-brown spores 

 in the ascus, and the excipulum and hypothecium are poorly developed. 



Claviceps purpurea. § — A. de Jaczewski placed a large number of 

 sclerotia of ergot in a box filled with earth, and left it exposed to all 

 weathers during the winter. Some of the sclerotia were scattered over 

 the surface of the soil, others were buried to a depth of 4 cm. Towards 

 the end of May growth began, and by the middle of June an immense 

 quantity of heads had appeared. Those that were buried appeared 

 above the soil at the same time, and differed only in sending up longer 

 stalks. Ascospores sowed on gelatin or agar germinated and formed a 

 felt of mycelium, with conidia similar to those produced in the Sphacelia 

 stage. 



Occurrence of Monilia in Sweden. || — Diseases of fruit-trees caused 

 by Monilia have been known in Sweden since 1894 : J. Eriksson has 

 now made a special study of them, to determine if possible the manner 

 in which they survive the winter. Sour cherries and certain apples 

 were selected for observation. The author describes in both cases -the 

 attack and progress of the disease ; in recent years the apples have 

 suffered more than the cherries. He finds that on branches of apples 

 that have been killed by the fungus there appear in spring innumerable 

 tufts of conidiophores of Monilia, with conidia that germinate readily. 



* Mycol. Centralbl., i. (1912) pp. 406-9 (1 pL). 



t Phytopath., ii. (1912) pp. 235-49 (7 figs.). 



X Mycologia, v. (1913) pp. 6-11 (1 pi.). 



§ BuU. Soc. Mycol. France, xxviii. (1912) p. 339 (1 pi.). 



ii Mycol. Centralbl., ii. (1913) pp. 65-78 (9 tigs.). 



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