596 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fungal Parasites of Tropical Cultivated Plants.* — A. Zimmerman? 

 gives a further list of injurious fungi on the plants of our greenhouses,. 

 &c. There is one member of the Hymenonrycetes, Corticium javanicum 

 Zim. The others are all microscopic, mostly found on the leaves or 

 twigs of the host-plant. 



Black Rot of Orang-es.f — N. B. Pierce describes as a new species 

 Alternaria Citri, a fungous disease of navel oranges which has attracted 

 attention in the orange-growing districts of California for some years 

 past. The fungus hyphge enter through cracks in the peel, and destroy 

 the cells of the pulp-sacs, which become black and bitter. Conidia are 

 formed upon the surface of affected tissues. 



Disease of Cultivated Chrysanthemums.!— P. Voglino has made 

 an extended study of the fungus causing this disease. It appeared first 

 in July, and several plants were entirely killed. In August and 

 Septemher there was not much spread of the disease, but in the two 

 following months it increased with great rapidity. The leaves were 

 disfigured by irregular brown spots which gradually extended over the 

 whole lamina. On these spots small pycnidia of a Phoma were formed, 

 called by Voglino P. Chrysanthemi. Examples of Phyllosticta leucan- 

 tliemi were also formed occasionally on greyish spots. At a later stage 

 the Phoma was replaced by Septoria Chrysanthemi, which continued to 

 develop and was, during the remainder of the season, the chief form of 

 the disease. By culture and infection experiments the writer proved 

 that the Phoma and Septoria were successive stages of the same fungus, 

 and that while the spores of Phoma had only a short existence, the 

 Septoria spores germinated after long intervals, and were able to resist 

 low temperatures. 



Black Rot.§— A. Prunet has published a note giving the result of 

 his treatment of Black Rot, a disease of the vine. The spores are 

 formed in pycnidia and are liberated by the action of water. The first 

 formation of these should be watched and the vines protected from the 

 first invasion of spores. He considers that they should be sprayed, say 

 ten days from the first unfolding of the leaves until the tree has bloomed. 

 It is not a wide-spread malady like mildew, and treatment need be applied 

 only where the disease has actually broken out. 



Some Fungus Cultures. || — Karl Holborn has been successful in 

 cultivating some of the fungi that cause diseases on hairs. His aim was 

 to transfer the parasite to other hairs. In a case of Trichorrhexis nodosa 

 that occurred in the hairs of a man's beard, he made a pure culture of 

 the fungus and developed a Mucor with its sporangia. From the culture 

 he induced a typical growth of the Trichorrhexis on hairs from a horse's 

 tail ; and from these hairs he again grew the Mucor. 



He applied the same methods to the culture of some of the Urcdineee. 

 He failed to make a growth from spores on artificial media, but he was- 

 more successful with the mycelium of the same fungi. He was prevented 



* Centralbl. Bakt., 2" Abt., viii (1902) pp. 803-5. 



t Bot. Gaz., xxxiii. (1902) pp. 234-5. 



X Malpighia, xv. (1902) pp. 329-41 (1 pi.). 



§ Comptes Reudus, exxxv. (1902) pp. 120-3. || Tom. cit., pp. 479-SO. 





