126 Pflanzenkrankheiten. 



Brooks. F. J., The development of Gnomonia erythrostoma 

 Pers. The Cherry-Leaf-Scorch disease. (Ann. Bot. XXIV. 

 95. pp. 585—605. 1910.) 



The foliage of trees attacked by this fungus is retained during 

 the autumn and winter. The leaves are first attacked in July, and 

 yellowish patches appear on the margin or near the midrib, fructi- 

 fications appearing on the under surface towards the end ot" August. 



The vegetative mycelium is intercellular and consists of multi- 

 nucleate cells, no haustoria being developed. 



Spermagonia are formed similar in structure to those of the 

 Uredineae The spermatia are long and threadlike, and possess the 

 cytological character of male cells, but are now considered to be 

 functionless. Thrichogynes arise in tufts of 2 — 5, and it is suggested 

 that their function is nov^ a respiratory one. Perithecial develop- 

 ment Start from „coils", with one or more differentiated ascogonia 

 in the middle of each. The development of the perithecia is descri- 

 bed, and it is notheworthy that the ascogenous cells appear to 

 arise by differentiation from ordinary cells, all traces of ascogonia 

 being lost. 



The only nuclear division observed takes place in the young 

 ascus, and the process is described. Only a Single process of re- 

 duction has been seen, which occurs in the first division. This 

 division may be either heterotype or brachy-meiotic, the analogies 

 rather pointing to the former. 



It is concluded that Gnomonia erythrostoma is an Ascomycete 

 in which only a Single nuclear division and a Single reduction 

 occur normally in the life cycle. W. E. Brenchley. 



Hopne, A. S., The Symptoms of internal disease and 

 , sprain (streak disease) in Potato. (Journ. agric. Sc. III. 3. 

 p. 322—332. 1910.) 



An introductory account of the literature of the subject is 

 given. The two diseases have been found to occur throughout nu- 

 merous samples of potato of known variety. Well developed inter- 

 nal disease has been detected in very young tubers. The flesh of 

 affected tubers in both diseases is marked with brown blotches 

 which may or may not form a connected System. The diseased 

 cells can be easily traced to within a few cells of the cork-la3^er, 

 while in Streakdisease they may occasionally be traced right up to 

 a slight injury in the surface of the tuber. No trace of any fungus 

 could be detected in any part of the diseased tissue. The cells are 

 killed, often retaining their starch unaltered. If the disease is propa- 

 gated from cell to cell it does not involve decay of the wall at the 

 time of the death of the cell. 



Storage experiments indicated that the disease did not spread 

 under such conditions. Cultural experiments showed that samples 

 of potatoes affected with Internal Disease and Streak-disease always 

 produced a certain proportion of affected tubers. The diseases in 

 question are frequently complicated by the pvesence o( P/iytopthora 

 infestans in the field, and Fusarium solanii in the pit or störe. 



W. E. Brenchley. 



Jaap, O., Cocciden Sammlung. Serie. VI. N*^. 6 1 — 72. (Ham- 

 burg, 25 Burggarten la, beim Herausgeber. September 1910) 

 In dieser Serie sind interessante Arten aus Norddeutsch 



