266 SUMMARY OF CUERENT EESEARCHES RELATING TO 



as most nearly allied to the Ustilaginese ; differing from tliem in its 

 highly complex fructification. Until transitional forms have been 

 found, he would erect it into a separate but closely allied family 

 under the name Graphiolaceae. 



Pourridie of the Vine.* — R. Hartig believes that the cause of this 

 disease is not as supposed, the " rhizomorph " of Agaricus melleus, but 

 a different fungus, Dematophora necatrix n. sp., clearly distinguished 

 from the former by its peculiar apical growth, the formation of sclero- 

 tioid agglomerations in the mycelium, and the form of the fructification. 

 The mycelium is parasitic, and rapidly kills not only the vine, but 

 many other trees which it attacks. Under favourable conditions, it 

 forms great numbers of branched conidiophores ; but since the peri- 

 thecial form is at present unknown, the systematic position of the 

 genus must remain at present undecided. Moesleria hypogcea ho 

 regards as saprophytic, and a secondary cause only of the disease. 



E. Prillieux,t on the other hand, while agreeing with Hartig that 

 the disease is not caused hj Agaricus melleus, looks on Boesleriahypogoea 

 as its true source. The coremium-like spores of this fungus he regards 

 as ascospores, formed eight in each ascus. 



Oospores of the Grape Mould.J — E. Prillieux states that he has 

 received from M. Frechou of Nerac germinating oospores of Perono- 

 spora viticola. The germinating oospores produce at once a mycelial 

 tube similar to that known in other species of Peronospora in which 

 the germination of the oospores has been seen. This is an important 

 step in our knowledge of the grape-mildew, since, inasmuch as the 

 conidia produce zoospores, it had been supposed by some that the 

 oospores would also produce zoospores, as is the case in the related 

 genus Cystopus. 



Pleospora gummipara.f —The fungus named by Beyerinck Cory- 

 neum gummiparum, connected with the flow of gum from woody trees, 

 has now been found by C. A. J. A. Oudemans in the perithecial form, 

 and been identified as belonging to the genus Pleospora, Sect. JHu- 

 pleospora. As it cannot be identified with any species hitherto known, 

 Oudemans calls it Pleospora gummipara, and describes the perithecial, 

 pycnidial, and conidial forms. 



Schizomycetes. ||— F. Neelsen gives a very useful epitome of the 

 present state of our knowledge respecting the life-history and classi- 

 fication of this class of organisms, referring chiefly to the labours of 

 Ehrenberg, Cohn, and Zopf . In the mode of investigation adopted 

 by the last-named authority, and the theory of the pleomorphism of 



* Hartig, K., * Der Wurzelpilze des Weinstockes,' 18 pp., Berlin, 1883. Also 

 Unters. aus d. Forstbot. Inst. Muncheii, iii. (1883) pp. 95-140,- and SB. Bot. Ver. 

 Munchen, Jan. 10, 1883. See Bot. Centralbl., xvi. (1883) p. 208. 



t Prillieux, E., 'La pourridie de la vigne, &c.,' 13 pp. (1 pi.), Paris, 1882. See 

 Bot, Centralbl., xvi. (1883) p. 208. 



t Bull. Soc. Botan. France. Cf. Science, ii. (1833) p. 831. 



§ Hedwigia, xxii. (1883) pp. 161-2. 



II Biol. Centralbl., iii. (1883) pp. 545-58. 



