ZOOLOGY ANIJ BOTANY MICKOSUOI'Y, EIC. 33 3 



tracheids were corroded. He also describes the carbonaceous structures, 

 like internal rliizoiuorplis, and compares them with external sclerotioid 

 bodies. 



A disease of cucumbers was observed by J. Hanzawa * in a green- 

 house in Japan. The seed had been imported from France in 1909, 

 and the seed produced had been used and had resulted in the diseased 

 plants. They grew normally at first until they were about a metre in 

 height and the fruits had formed. Then the leaves became discoloured 

 and dropped off, the stalks were next attacked and the plant died. 

 Several fungi — mostly saprophytic — were determined on the decaying 

 part of the plant, but the real cause of the trouble was diagnosed as 

 NectrieUa Cucumeris sp. n. It grew on the roots and on the stems that 

 had been partially covered with soil. 



H. T. Giissow f has determined the presence in Canada of powdery 

 scab of potatoes {Spongospera subterranea). It is easily distinguished 

 from other forms of scab by the appearance of the spores, which form 

 hollow spore balls. Dissemination of the fungus is probably effected by 

 diseased seed-potatoes. 



C. T. Gregory % lias described a rot of grapes caused by a pycnidial 

 fungus Cryptosporella viticola. It makes its appearance on the berries 

 as a dark bluish-purple spot, chajiging later to brown. Finally 

 pycnidia are formed, and the berries gradually shrivel. The fungus has 

 been identified with one that attacks grape shoots. 



A large number of fungous diseases, especially rotting diseases, are 

 caused by Fusarium^ and there is much confusion and uncertainty 

 as to the identification of species, etc. H. W. AVollenweber § has made 

 a comparative study of many of the forms. He finds that the species 

 can be grouped in sections according to characters that are both physio- 

 logical and morphological ; thus in one section are included the species 

 that cause wilt diseases ; in others are found the fruit and tuljer rots, 

 etc. Incidentally he mentions that the potato is the host of thirty 

 different forms. 



E. Melhus ll found that certain cases of pea blight were due to the 

 fungus Septoria Fisi, so he instituted a number of infection experiments 

 to determine the extent of the attack. After the infection the fungus 

 spreads outwards till the whole leaflet is destroyed ; it then enters the 

 petiole and travels into the stem, and if the infection is sufiiciently 

 vigorous, the host-plant is soon killed. The winter or perfect fruiting 

 form was not found, though the author is sure that there must be one, 

 seeing that the Septoria spores gradually lose their vitality as the season 

 advances. 



A disease of wheat IF known as " White-heads " or " Take-all " has 

 been found to be caused by the attack of a fungus Ophioholus graminis. 

 The fungus matures on the stubble and only mycelium is present in the 

 growing and seeding plants. The plants are attacked at an early stage ; 



* Zeitschr. Pflanzenk., xxiii. (1913) pp. 65-72 (2 pis. and 3 figs.), 



t Phytopath., iii. (1913) pp. 18-19 (1 pi. and 1 fig.). 



i Phytopath , iii. (1913) pp. 20-3 (2 figs.). 



§ Phytopath., iii. (1913) pp. 24-50 (1 pi. and 1 fig.). 



:| Phytopath., iii. (1913) pp. 51-8 (1 pi.). 



t Journ. Board Agric, xix. (1913) pp. 1020-5 (1 pi.). 



