NOTES AND ABSTRACTS. 



301 



consists of rounded cells with relatively small intercellular air-spaces ; 

 and there are usually stomata in the epidermis, having the aperture 

 closed up or nearly so. Comparatively little is known concerning 

 the physiology, or even the structure and development, of the aerating 

 system in plants, and Vouk's interesting contribution may be the 

 means of calling attention to this line of investigation ; a fuller know- 

 ledge of the relation of the aerating system to the environment is 

 especially desirable. — F. C. 



Podocarpus formosensis. By R. Dummer (Gard. Chron., p. 295 ; 

 October 19, 1912 ; with fig.). — Publication of this new species. 



E. A. B. 



Pollination Question, The (U.S.A. Exp. Stn., Oregon, Circ. 

 Bull. 20, May 1912). — Some of the practical results of severalfyears' 

 work in this connexion are set forth. The conclusion is arrived at 

 that in general cross-pollination does not affect the flavour, quality, 

 or colour of the fruit, but merely its size, the percentage of set, and 

 the uniformity of the crop. Sporadic instances of apparent effect are 

 attributed rather to bud variation. — A. P. 



Potato Sprouts, Ingrowing. By C. Stuart Gager (Bot. Gaz., 

 pp. 513-524 ; Dec. 1912 ; with 6 figs, and 1 plate). — The author 

 figures and describes certain curious ingrowing shoots of the Potato 

 produced in an unheated chamber which was neither dark nor damp. 

 They do not digest their way through the tuber, but pass through by 

 mechanical pressure. They do not penetrate through the uninjured 

 skin from the outside, but easily penetrate it from the inside. The 

 branches often form small tubers. — G. F. S. E. 



Potato Tubers. On the Rotting of Potato Tubers by a new 

 Species of Phytophthora. By G. H. Pethybridge (Sci. Proc. Roy. 

 Dublin Soc, vol. xiii., No. 35, pp. 529-565 ; March 1913 ; 3 plates). — 

 The new disease of Potato tubers is caused by a fungus which under 

 natural conditions appears to remain sterile. The author isolated the 

 fungus with great care and found that it grew readily as a saprophyte 

 in artificial culture, and that on certain substrata (especially on media 

 derived from Oats) it produced reproductive bodies freely. The 

 parasite proved to be a new species of Phytophthora, and is named 

 P. erythroseptica. 



The external symptoms of the disease are well marked. The 

 tubers, often before lifting, become soft and watery, and when cut open 

 and exposed to the air turn pink : hence the name ' Pink Rot.' Later 

 the pink colour gives place to a purple-black. The isolation of the 

 fungus and method of culture are described in detail, as is also the 

 process of spore development. The development of the oogonium 

 is so unlike anything previously known in the genus that the writer 

 examined a number of allied forms, with the result that he found other 



