614 SUMMAllY OF CURRENT RESEARCHES RELATING TO 



Uredinese.* — W. H. Long describes a series of Ravenelia species 

 collected by biro in Texas, several of them new to science. Biological 

 notes are added, and Ravenelia galls are described and compared in two 

 species ; in both there is a leaf and a gall form, teleutospores usually 

 occurring on leaves, while on the galls are found only uredospores. 



J. C. Arthur t reports on his cultures of Uredinese in 1916 and 1917. 

 There are seven successful cultures in 1916 of Fuccinia, the teleuto- 

 spores of which have been sown on the alternate hosts. All of these had 

 been previously reported. In addition, Uromyces Sporoioli gecidiospores 

 from Allium dellatum were sown on Sporobolus vaginsefiorus, and the 

 teleutospores on Puccinia Vernonise were sown on the same host. Both 

 cultures were successful. 



For the year 1917 four successful cultures of Puccinia and Uromyces 

 are confirmed, while two new cultures are reported : Puccinia Sporoholi 

 teleutospores successfully sown on Allium cernuutn, A. Nuttallii, and 

 Lilium umbellatum, while Uromyces magnatus teleutospores from Spartina 

 Michauxiana produced eecidia on Polygonatum hiflorum, P. commutatum, 

 and Vagnera stellata. 



H. S. Jackson:}: reports two new forest rusts from North- west 

 America : Chrysomyxa Weirii on Picea Engelmanii and Melampsora 

 occidentalis, the teleutospores of which grow on various Populus trees. 



With reference to the dispersal of Cronartium ribicola, Gr. F. Gravatt 

 and Rush P. Marshall § find that various small animals act as the bearers 

 of the spores, which adhere to the bodies of the animals. The animals 

 feed on the spores, remains of which have been found in their excreta. 

 It was also proved that alimentation had lessened the vitality of the 

 spores. 



Parasitism of Ustilago Zese.H — F. J. Piemeisel has studied, by 

 means of inoculation experiments, the occurrence and life-history of this 

 fungus which occurs on the leaves, ears, etc., of the host-plant. As a 

 plant may be affected at different areas while neighbouring plants are 

 free, it was surmised that the disease might travel to different parts of 

 the plant within the tissues. This, however, as already pointed out by 

 Brefeld, is not the case, attacks being due to repeated infection. Any 

 injury to the host-plants, such as close planting, very early and very 

 late planting, are all conducive to disease. Vigorously growing plants, 

 between two and three feet high, are very susceptible to attack. The 

 spores of the fungus may germinate as soon as mature, but they retain 

 their viability for a number of years (at least five years). They are 

 killed, however, after having been kept in a silo for a few weeks, owing 

 probalaly to the presence of silage acids. Sporidia which were produced 

 from the germinating spores are almost as resistant as the spores, and 

 are not much injured either by desiccation or by freezing. 



* Bot. Gaz., Ixiv. (1917) pp. 57-69. 

 t Mycologia, ix. (1917) pp. 294-303. 

 t Phytopathology, vii. (1917) pp. 352-5. 

 § Phytopathology, vii. (1917) pp. 368-78. 

 II Phytopathology, vii. (1917) pp. 294-307. 



