222 SUMMARY OF GUHRENT RESEARCHES RELATING TO 



short and without forming sporidia. The author also observed that the 

 first stage in germination was the extrusion of a naked mass of 

 protoplasm from the spore, which later lays down the membrane of the 

 promycelium. The sporidia also are at fii'st minute naked points of 

 protoplasm pressed out through a cleft on the apex of the sterigma by 

 internal turgescence ; the sporidial membrane is also formed later. 



Other experiments were undertaken to determine the length of time 

 that the sporidia could remain capable of germination. The capacity 

 was of short duration in an atmosphere not thoroughly saturated. 

 They lost all power of growth in an hour when the air was saturated to 

 90 p.c, and even in 100 p.c. of saturation they did not long remain 

 vital. These experiments proved the impossibihty of rust dissemination 

 by means of sporidia to any great distance. 



J. C. Arthur * publishes eleven new species of Uredineti; belonging 

 to the genera Uropyxis, UromyceH, Purcinia, ^cidium and Uredo. 

 Four of these are short cycle forms, and are interesting because they 

 occur on hosts that also bear long cycle species. 



B. 0. Dodge t discusses the effect of the host on the morphology of 

 certain species of GymnosporaiKjium. Special attention is given to 

 G. biseptatum, which is perennial in tlie branches or trunk of 

 Chamaecyparis, which is characterized by a great variability in the 

 number of spore-cells ; and G. fraternum, a folliculous parasite on the 

 same host. He considers that these two, however, may be the same 

 species, as their ascidia on Amelanchier are much alike. The discussion 

 mainly deals with inoculation experiments of the two forms from one 

 host to another. 



Yellow Rust of Cereals {Puccinia glumarum) has recently been 

 discovered in N. America by M. A. Carleton % on several varieties of 

 wheat in Arizona and also in other districts. Up to July it had not 

 been found in any place east of the Rocky Mountains. It is a common 

 rust in Europe. 



J.C. Arthur§ has given an account of the Uredinales of Porto Rico, 

 based on collections made by F. L. Stevens. A few are new species ; 

 all those recorded are described at length, and an index is added of 

 Uredinales of the West Indies, with an index to the host plants. 



A. W. Borthwick and Malcolm Wilson || describe two Rust Diseases 

 of the Spruce : — Ghrysomyxa Rhododendri was first discovered in Britain 

 by D. A. Boyd in June 1913 at Douglas Castle, Lanarkshire. The 

 fecidial stage on Picea exceha was discovered in S.W. Scotland some 

 months later. The life stage of the fungus was already well known. 

 The disease is not likely to spread, as the species of Rhododendron on 

 which it grows are rare. Ghrysomyxa Abietis completes its life history 

 on the Spruce, and is therefore a more dangerous rust. Though 

 appearing only recently in Scotland it has already done considerable 

 damage. 



•&^ 



* Bull. TorreyBot. Club, xlii. (1915) pp. 585-93. 

 + Bull. Torrey Bot. Club, xlii. (1915) pp. 519-42 (2 pis.). 



J Science, n.s. xlii. (1915) pp. 58-9. See also Bull. Agric. Intell. Rome, vi. 

 (1915) p. 1408. 



§ Mycologia, viii. (1916) pp. 16-33. 



II Notes Roy. Bot. Gard. Ediaburgb, ix. (1915) pp. 63-9 (1 pi.). 



