ADDENDA 573 



production of otherwise profitable crops, and in many 

 instances industries have been abandoned on this account. 



The author evidently looks upon the present methods of 

 combating fungus diseases as both costly and unsatisfactory, 

 and indicates the need of immune varieties. 



' One of the most effective methods of dealing with plant 

 diseases is to improve our crops so that they will be less 

 subject to injury. When we can introduce into our agricul- 

 ture varieties possessing a degree of natural immunity and 

 thereby avoid both the loss from disease and the necessity 

 for the more or less expensive treatment by sprays and other 

 means, a double economic gain will be secured.' ('Year- 

 Book,' United States Department of Agriculture.) 



Black scab of potato. Professor Percival has just published 

 an account of the organism causing black scab in potatoes, 

 and comes to the same conclusion that I expressed at a 

 meeting of the Linnean Society some months ago, and in this 

 book on p. 98, viz., that the organism belongs to the genus 

 Synchytrium, Percival suggests the name Synchytrium 

 endobioticum, which having priority of publication, will be 

 accepted in the future. The specific name endobioticum 

 implies that Percival considers his fungus to be identical 

 with Chrysophlyctis endobiotica (Schilb.). At the page quoted 

 above I have stated reasons for considering it to be quite 

 distinct from Schilbersky's fungus, hence suggested the name 

 Synchytrium solani. 



Percival J., CentralbL filr Bakt. Parasit. u. Infectionskr., 

 p. 440, 1909. 



Conifer bud disease. Dr. Borthwick has described a 

 disease of Picea pungens, caused by Cucurbitaria piceae 

 (Borthwick). The fungus forms a thick, black, crust-like 

 stroma completely enveloping the bud. On this stroma 

 numerous black perithecia are eventually produced. 



Mycelium intercellular, perithecia closely crowded, stipitate, 

 springing from the stroma, black, carbonaceous ; asci clavate, 

 4-6-spored, spores uniseriate, cymbiform, 4-io-septate, muri- 

 form, 20 X 6 /a ; paraphyses filiform. 



Borthwick, A. W., Notes from Roy. Bot. Gard. Edinb., 

 No. 20, p. 259 (1909). 



