322 The Botanical Gazette. [November, 



by a deficient supply of water, which may be occasioned either by a 

 poor development of the root system owing to a lack of potash in the 

 soil, or to lack of moisture in the soil owing to poor cultivation. The 

 spots appear on the lower leaves first, and spread to the upper. They 

 are of very different form and size, frequently enlarge and fuse, and 

 sometimes the tissue involved breaks away entirely. The whole mis- 

 chief is often wrought in two or three days. Is not the plant subject 

 to the same trouble m this country? Better tillage, selection of 

 ground, with proper exposure and rotation of crops are advised. 



The study of the peach yellows has been a most discouraging task ? 

 but Mr. Erwin F. Smith, who has for several years been at work upon 

 the disease for the Department of Agriculture, has shown great perse- 

 verance in its investigation. In an address before the Peninsula Hor- 

 ticultural Society at Easton, Aid., he asserts that the disease on that 

 f>eninsula is increasing, and that he has definitely ascertained by mocu- 

 ation experiments that the disease is contagious. No preventive 

 measures or treatment have been able to check it in the least. In 

 Michgan, however, the eradication of every diseased tree has practi- 

 cally suppressed the trouble, and this is recommended to the Delaware 

 and Maryland growers. While several organisms have been found 

 associated with the diseased tissues, none has yet been proved to be the 

 cause of the malady. 



The last part of Pittonia (Vol. II., part 10), just issued, is an inter- 

 esting one, as all the parts are. Of course numerous new species are 

 described. Achaetogeron is included under Erigeron and its species 

 properly renamed. The most interesting part is always that which 

 deals with ancient names of genera, as one never knows what unheard 

 of name is to be suggested for his old friends. In the present paper 

 9 genera are thus treated and their 79 species renamed. Polanista is 

 changed to Jacksania Raf., Wistaria to Kraunhia Raf., Riddellia to 

 Psilostrophe DC, Troximon to Agoseris Raf., Pyrrhopappus to Sitilias 

 Raf., Cardylanthus to Adenostegia Benth., Echtnospermum to Lapp"!* 

 Momch., Mioostxlis to Achroanthes Raf., and Sxmplocarpus to Spathv- 

 ema Raf. A new and promising field of nomenclature is opened up 

 in the case of revertible names. No genus is now to be allowed to 

 bear a revertible name (that is one that appears as the more ancient 

 svnonvm of any other genus). Accordingly, simply byway of men- 

 tioning -but a few out of many changes " which are promised, the 

 author proceeds to coin generic names. Picket in^ia Xutt. is renamed 

 Xylothermta; Nuttallia T. & G. is Osmaronia; Darlingtonia Torr. is 

 Ckrysamphara ; Crantzia Xutt. is Lihcopsis; Rafinesquia Nutt. is i\c- 

 mosens; Tarreya (used with 5 genera) \%Tumion (this time of Raf.). In 

 the same part. Professor Greene replies to the criticisms that have been 

 made of his citation of ancient botanical authors, and also inveighs 

 against the Negundo Negundo and Catalpa Catalpa departure in 

 nomenclature. r 



