274 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Potato Fungus.* — Ilcrr J. Brunchorst has investigated the con- 

 ditions of a common disease of potato tuhers, which is known hy tho 

 names " skurv," " schorf," " grind," &o., and which seems most likely to 

 occur on soil where potatoes have not for long, or ever hefore, been 

 planted. The disease has been usually referred to something in the 

 soil, but the author maintains that it is due to a parasitic fungus. It is 

 a myxomycete nearly allied to Plasmodiophora, and it is proposed to 

 designate tho genus and species Spongospora Solani. The brown crusts 

 or spots which cover the tubers are due to knots or aggregations pro- 

 duced by tho fungus, and are covered by the normal rind of the potato. 

 Details as to tho nature of these fungoid growths, the time and conditions 

 of their occurrence, arc communicated. 



Taphrina.j — Mr. B. L. Eobinson has recently studied a number of 

 American and European species of the genus Taphrina. The species 

 combined by Sadebeck, in 1883, into a single genus, were formerly 

 classed in three closely related genera, Taphrina Fries, Ascomyces 

 Mont, et Desm., and Exoascus Fuckel. The presence of a Taphrina is 

 manifested in the host in one or more of several ways, namely, by the 

 occurrence on the leaves of roundish or irregular blotches, by a curling 

 or crisping of the leaves, by a swelling out of the softer parts of the 

 leaves between the nerves, by deformity of the fruit, and lastly, by the 

 swelling and distortion of the twigs and young branches. 



The author appends to the paper a synopsis of the American species 

 examined. The primary divisions being (1) Mycelium penetrating 

 intercellularly the inner tissues of the host ; and (2) Mycelium spreading 

 itself just below the cuticle and not entering the tissues of the host. 



Disease affecting Cherry and Plum-trees.:]: — M. P. Vuillemin de- 

 scribes a fungus which has committed great ravages among the cherry 

 and plum-trees in Lorraine. 



In the first days of May the trees begin to droop, and at the end 

 of the same month most of the leaves of tlie cherry-trees are covered 

 with spots. Each spot is caused by a mycelium which is the product of 

 a spore belonging to a conidial condition which has been named 

 Coryneum Beijerinki Oud. The spore fixes itself on the under side of 

 the young and slightly viscous leaves, and emits its tube which 

 penetrates between two epidermal cells. The filaments enlarge and 

 segmentation takes place, and in the centre of the spot one or more 

 polyhedric cells are formed, which are very similar to the fructification 

 formed in the genus Entyloma. These polyhedric cells finally assume 

 the characteristic appearance of the conidia of Coryneum. Pycnidia are 

 also developed towards the end of June ; they are more abundant on the 

 under surface of the leaf. 



Oidium Fragariae.§ — Dr. C. 0. Harz describes this new species, 

 which is very destructive to cultivated strawberries, growing on the 

 under side of the leaves, and causing abortion of the flowers or fruit. 

 Conidia were the only reproductive organs seen. It closely resembles 

 0. Buborum, and may possibly be identical with it. 



* Bergens Mus. Aarsberetning for 1886 (1887; pp. 219-26 (1 pi.), 

 t Ann. of Bot., i. (1887) pp. 163-76. 

 X Morot's Journ. Bot., i. (1887) pp. 315-20. 



§ SB. Bot. Verein Miinchen, Jan. 17, 18S7. See Bot. Oentralbl., xxxii. (1887) 

 p. 313. 



