ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621 



A disease of Datura Stramonium due to a brown mould, AUernaria 

 crassa, is described by R. D. Hands.* The leaves are used for the 

 extraction of atropin or daturin, and the presence of the fungus lessens 

 materially the value of the leaves. Many cultures were made to ensure 

 the identity of the fungus, which Rands holds to be synonymous with 

 Cercospora crassa, Macrosporium Solani, and others. 



L. E. Miles f describes a number of fungoid diseases from Porto 

 Rico : a leaf-spot of the bean, due to Isariopsis griseola ; Cercospora, on 

 tobacco and other plants ; Pucciniopsis Caricse, on the paw-paw, of special 

 interest on account of a curious fungus, Zygosporium oschioides, that grows 

 saphrophytically on the Pucciniopsis spots, and other leaf forms on the 

 avocado, the yam, and on Paspalum. 



Wood-destroying Fungi. J — J. R. Weir gives additional notes on the 

 fungi that attack both coniferous and deciduous trees. They are all 

 forms of Polyporaceas, except Schizopliyllum commune, which has been 

 found once on Tsuga heterophyUa. 



Dry-rot of Potatoes.§~G. H. Pethybridge and H. A. Lafferty 

 have examined this rot of potatoes largely with a view of determining 

 the species of Fusarium by which it is caused, and which had been 

 described in a previous research on the subject as F. Solani, a collective 

 species. WoUenweber had found that rot in potatoes might be caused by 

 eight different species of Fusarium, the most virulent being F. cocruleum, 

 which has been recorded as British. The authors have investigated 

 eleven distinct cases of the disease, and in every case the organism 

 causing it was F. cocruleum. It is essentially a storage disease, and 

 owing to the action of the fungus the potato loses water and shrinks, 

 becoming finally light in weight, dry and hard. Artificial cultures were 

 made, and in most of them the characteristic blue colour, to which the 

 fungus owes its name, was produced. 



Infection generally takes place through wounds, but may also occur 

 through scab spots or through the lenticels, eyes, or young sprouts of unin- 

 jured tubers. Potatoes become more susceptible to infection as they 

 Ijecome more mature. 



Disease of Pitch Pine Timber. |j — L. 0. Overhots ascribes this 

 disease to the action of Polyporus amorphus ; it causes a characteristic 

 decay of the sapwood of Pinus rigida, and has also been collected on 

 wood of Pinus Strohus, P. pungens and T'suga canadensis. The disease 

 was observed on fallen trees in the vicinity of State College, Pennsylvania. 

 The decayed wood became darker in colour, and the spring wood is 

 decayed before the summer wood. The fungus attacks the cellulose of 

 the medullary rays, dissolving it out, then the bordered pits, and finally 



* Phytopathology, vii. (1917) pp. 327-37 (4 figs.), 

 t Phytopathology, vii. (1917) pp. 345-51 (3 figs.). 



* Phytopathology, vii. (1917) pp. 379-80. 



§ Sci. Proc. Roy. Dublin Soc, xv. (1917) pp. 193-222 (2 pis.). 

 II Mycologia, ix. (1917) pp. 261-70 (2 pis.). 



