ZOOLOGY AND BOTAxNY, MICROSCOPY, KTC. 497 



borne in chains on conicliophores. The disease is very easily cultivated 

 on artificial media from either type of spore. 



P. J. O'Gara * describes a new leaf-spot disease on Polygonum 

 Persicaria due to a species of Septoria {S. Persicarine sp. n.). The 

 spots on which the pycnidia are borne are less than 1 cm. in diameter, 

 grey or brown with a narrow limiting purple line ; the spores are 

 filiform, long and narrow. 



T. H. Watson t has described as diseases of the spruce {Picea excelsa) 

 in Scotland ; Trametes radiciperda, a root fungus very common ; Chrf/- 

 somyxa Abietis, which is confined to old mature trees ; and Lcphodermium 

 jnacrosporum, which attacks the needles and has caused the death of 

 many trees. Cucurhitaria Piceae was also observed on the buds of spruces 

 seventy years old. 



A. Lendner % describes two parasitic diseases : Pestalozzia Briardi, 

 which was found at the base of a vine-shoot inducing cancerous forma- 

 tions ; and Lophionema Chodati, which occurs as small black pustules on 

 the cones of Pinus sylvestris. 



Storage Rots of Economic Aroids.§ — The corms and tubers of various 

 Aroids {Colocasia, Alocasia, Xanthosonui) are used for food in America, 

 and in storage are largely liable to rot. L. L. Harter has examined 

 these rots, and gives an account of the fungi mainly responsible. They 

 are : — Java black-rot, due to different species of Diplodia ; powdery 

 grey -rot, caused by Fusarium Solani ; Sclerotium-rot, by Sclerotium 

 Rolfsii ; and a soft-rot cansed by Bacillus cartovorus. The writer 

 describes the attack and the effect of these diseases, and gives suggestions 

 as to prevention and cure. 



Research on Plant Diseases. — E. Gaumann || has conducted a 

 research on the distribution of Peronospora parasitica, a parasite of 

 cruciferous plants, in which specialization is carried to a very high 

 degree. Infection experiments on various hosts within the family were 

 carried out, and careful morphological observations were made on the 

 variations in conidia, conidiophores, and oospores. The author has 

 proved a very high degree of specialization. 



0. A. Pratt IF has experimented with disease-free potato tubers on 

 virgin soil in Idaho. He found that the crops were by no means free 

 from disease. Several species of fungi — Fusarium, Rhizoctonia, and scab 

 due to Actinomyces, were of common occurrence. A smaller percentage 

 of disease occurs, however, on land previously sown with barley and 

 lucerne. 



* Mycologia, ix. (1917) p. 248 (1 pi.) 

 ; t Trans. R. Scott. Arbor. Soc, xxxi. (1917) pp. 72-3. 



X Bull. Soc. Bot. Geneve, viii. (1917) pp. 181-5. See also Bull. Agric. Intell. 

 Rome, viii. (1917) pp. 809-10. 



§ Journ. Agric. Research, Washington, vi. (1916) pp. 549-71 (4 pis.). See also 

 Bull. Agric. InteU. Rome, vii. (1916) pp. 1852-4. 



1] Centralbl. Bakt., xlv. (1916) pp. 575-7. See also Bull. Agric. Intell. Rome, 

 vii. (1916) p. 1851. 



^ Journ. Agric. Research, Washington, vi. (1916) pp. 573-5. See also Bull. 

 Agric. Intell. Rome, vii. (1916) pp. 1851-2. 



Oct. 17 til, 1917 2 L 



