86 SUMMARY OF CURRENT RESEARCHES RELATING TO 



was determined as Dictyuchus from the retention of spores in the 

 sporangium while they germinated, with the liberation of zoospores- 

 These zoospores were observed to come to rest and encyst. After a 

 time some of these encysted spores germinate by hyphse. Many of 

 them, however, emit zoospores which are biciliate, and thus exactly 

 similar to those formed in the sporangium. The writer is of opinion 

 that this secondary zoospore formation will be found general in Dicty- 

 uchus. No sexual organs were formed, and it was thus found impossible 

 to determine the species. A. Lorrain Smith. 



Study of Synchytrium.— W. Rytz {Beih. Bot. Oentralbl, 1917, 34,. 

 343-72, 3 pis. ; see also Ann. Mycol.., 1917, 15, 289). Synchytrium 

 Taraxaci is parasitic in the epidermis of Taraxacum officinale. The- 

 zoospores penetrate directly from the outside into the host-cell, the 

 latter enlarges, and in due time division of the parasitic nuclei begins 

 up to a large number. Division is always mitotic. A. L. S. 



Specialization of Peronospora on some Scrophulariacege. — Ernst 

 Gaumann {Ann. Mycol, 1918, 16, 189-99, 4 figs, and diagrams). There 

 is considerable biological specialization among Peronosporese, and there- 

 is also considerable difference in spore sizes. Gaumann has taken up 

 the question with regard to a limited number of what he terms collective 

 species. He describes seven new species. . A. L. S. 



Study of Plasmopara. — Alfred Wartenweiler {Ann. Mycol.^ 

 1917, 15, 495-7; 1918, 16, 269-99, 3 pis., 12 figs.). The author 

 finds that when a species of Plasmopara grows on different hosts,, 

 there is considerable variation in conidia and conidiophores. Thus for 

 Plasmopara nivea he tested sizes from twenty different hosts. He gives- 

 the number of measurements and the average size of spores on each ; 

 they vary from 16 "99 ft x 16*21 /u. in the first host in even higher 

 measure to 28 /x x 21'48/t on the last. He made similar tests for 

 P. pygmaea and P. densa, which showed somewhat equal variations. 

 The conidiophores were also examined and found to vary according to- 

 the host. 



In the second paper he continues the study of conidia and conidio- 

 phores. He also gives the results of a research on the wintering of 

 Plasmopara nivea. He claims to have proved that the mycelium passes 

 the winter in Laserpitium latifoUum. He has established this |in plants- 

 from many districts, but cannot say if it is of universal occurrence. He- 

 gives in a summary at the end a comparative account of the various- 

 species examined. A. L. S. 



Classification of the Phacidiales. — Fr. von Hohnel {Ber, 

 Deutsch. Bot. Gesell, 1917, 35, 416-22). The Phacidiales comprise 

 discomycetes without or with a stroma and with a carbonaceous ascoma 

 which opens in lobes. Van Hohnel divides the order into six families. 

 Diagnoses of these and of the genera are given. A. L. S. 



Study of Hypocreacese. — I. Weese {Siiz.-Ber. Akad. Wiss. Wien 

 Math. Nat. Kl. Abhl, 1916, 125, 467-575, 3 pis. 15 figs.). A critical 



