156 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



"both the black and the Canada poplars, and is a very rapidly growing 

 cancer-producing fungus. The pycnidia of the fungus are formed 

 beneath the bark, and when mature produce the spores in tendrils, at 

 first cream-coloured, but gradually changing to a tawny -olive or 

 walnut-brown colour. There is a suggestion — not proved as yet — that 

 it may be a stage of Cmanglum populneum. 



The authors have traced the history and occurrence of the fungus 

 in Europe and America, and they recommend the destruction of 

 diseased trees. As a preventitive, cuttings should be dipped in 

 Bordeaux mixture before planting. 



Parasitic Saccharomycete of the Tomato.* — Albert Schneider 

 describes this fungus, which was found on a tomato probably from 

 Cul)a or from Mexico. All the stages of growth and development were 

 present on the slides that were mounted. The vegetative cells were 

 seen to multiply by budding. The ascopores are formed in spore-sacs 

 which result from the gametic union of two normal elliptical vegetative 

 cells. Eight spores are formed in each sac ; they are two-celled, rather 

 slender, and taper to a point. The fungus is a true parasite, as it 

 develops in and upon living; tissues, and will not develop in the presence 

 ■of decay. 



Chondromyces Thaxteri.t — J.H. Faull describes this new species of 

 Myxobacterium, pointing out the affinity of these organisms with the 

 Myxomycetes, especially with the Acrasiea3, their colours being strictly 

 comparable to the fructifications of that group. In the above species 

 the pseudoplasmodia are yellow or flesh-coloured, the " fructifications " 

 yellow, the stalks simple or branched. It appeared on deer-dung from 

 Algonquin Park Forest Reserve, Ontario, and was successfully cultivated 

 during two years. The different culture stages arc carefully described. 



Plant Diseases.— AY. H. Tisdale J has described a black spotting of 

 tomato fruits due to a species of Melanconium. The spots are small, 

 seldom reaching an eighth of an inch across, and, if independent of 

 wounds, are confined to the superficial layers of the tomato. Wound 

 infections involve the destruction of the deeper tissues of the fruit. 

 The disease was easily induced by spraying with a spore-suspension in 

 water, but in this case infection only took place where the fruits were 

 wrapped with moist cotton after spraying. The wound type of spot 

 was produced by inserting spores in the fruit by needle-pricks. 



G. H. Pethybridge§ publishes a report on investigations into 

 diseases of potatoes during 1915. He discusses first the ordinary 

 blight, Phytophtltora infestans. It has been found that after a season 



* Phytopathologv, vi. (1916) pp. 395-9 (4 figs.). 



t Bot. Gaz., lxii."(1916) pp. 226-332 (2 pis.). 



X Phytopathology, vi. (1916) pp. 390-4 (3 figs.). 



§ Dept. Agiic. Techn. Instr. Ireland, xvi. No. 4 (1916) 84 pp. (16 figs.;. 



