98 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of a previously existing fficidio-generation ; and from this it would 

 appear to follow that the tecidio-form, and not the telcuto-form, is the 

 original one. The author thinks it must he assumed that originally one 

 and the same mycelium had the power of producing hoth teleutospores 

 and fecidiosporcs ; and that the distinction of the two generations ori- 

 ginated in tho alternations of climate ; and the occurrence or absence 

 in any species of the uredo-generation depends, in the same way, on its 

 adaptation to the climatal conditions in which it is found. The most 

 essential difference between tho Uredinere and the Ascomycetes lies in 

 the capacity of the former to produce sporidia, which do not fail in any 

 known species, and must therefore be regarded as the most essential 

 member in tho cycle of development. 



All three generations may occur on the same host in the course of a 

 year, or they may be confined to different hosts. In the heteroecious 

 species the particular host on which the teleuto-form or jecidio-form 

 will develope depends in no way on its systematic position, but on the 

 facilities presented for the spread of the spores. Autoecious Uredinese 

 can hibernate in the uredo-form. In all probability it is the teleuto- 

 spore-generation that has migrated from its original host to a different 

 one. 



Grape-disease— Comothyrium diplodiella.* — M. E. Prillieux has 

 come definitely to the conclusion that Comothyrium diplodiella is a true 

 parasite, and not merely saprophytic. Professor Pirotta, of Kome, allowed 

 ripe spores to germinate in spring-water, and infected perfectly healthy 

 grapes with them. The disease showed itself in four to six days. M. 

 Frechon corroborated this, and M. Prillieux has also satisfied himself 

 by experimental inoculation that the fungus is truly parasitic. 



New Disease of Lemons-f — Sig. G. Gasperini describes a new disease 

 exceedingly destructive to the lemon-crop in Italy, spreading with very 

 great rapidity, and entirely destroying the fruit, which it causes to fall, 

 and to which it gives a nauseous smell. He finds it to be caused by the 

 mycelium of several Hyphomycetous fungi, of which the following species 

 are described as new, and their diagnoses given, viz. : — Aspergillus 

 violaceo-fuscus, A. elegans, and A. variabilis. On the surface of the 

 lemons was also found a species of Saccharomyces, which he calls S. Gitri, 

 consisting of oval, elliptical, or cylindrical cells 3-6 ■ 5 li long by 1-2 //, 

 broad, united into colonies which branch in a variety of ways. They 

 contained from one to three very minute spores, and were readily culti- 

 vated on dilute sterilized lemon-juice. 



New Pythium.J — Herr W. Wahrlich proposes the name Pythium 

 fecundum for a new saprophytic species found in a stream springing 

 from the Phone Glacier. It presents in some respects a transitional form 

 between the Peronosporese and the Saprolegnieae. The zoosporangia 

 are 2 /x broad, 120-160 /x long, and scarcely distinguishable from the 

 ordinary hyphae ; the zoospores are reniform, 4 fx wide by 6 fx long, and 

 with two cilia on their concave side. The oogonia are of two kinds ; in 

 those first formed each oogonium is impregnated by one or two antheridia 

 formed in close proximity to the oogonium. The second kind are some- 

 times produced on the same branch as the first, but later. These are 



* Comptes Eendus, cv. (1887) pp. 1037-8. 



t Atti Soc. Tosc. Sci. Nat, viii. (1887; pp. 315-41. 



% Ber. Deutsch. Bot. Gesell., v. (1887) pp. 242-6 (1 pi.). 



