168 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



generally having P. trifloraior one parent ; Americana group (P.americana), 

 the variety " Hanson " only being found of any use in Georgia, all the 

 others lacking in constitution ; Hortulana group (P. hortulana), to which 

 belong the only plums (excepting Japan) worthy of cultivation com- 

 mercially ; Chicasaw group (P. chicasa and P. angustif olio) ; Myrobalan 

 group (P. myrobalana or P. cerasifera) containing few of commercial 

 value, but good as nursery stock ; European group (P. domestica), all of 

 which rot quickly and are worthless in Georgia ; dwarf plums (P.pumiJa), 

 merely curiosities. Insect enemies and fungoid diseases are described. 

 A list of varieties is given, with popular descriptions of each. — F. J. C. 



Plums, Japanese and Hybrid. By H. N. Starnes (U.S.A. Exp. 

 Stn. Georgia, Bull. 68 ; August 1905). — The superiority of the Japanese 

 over the native plums for cultivation in Georgia is pointed out and descrip* 

 tions of a large number of varieties (which are figured natural size) are 

 given in simple language.— P. J. C. 



Poisonous Plants, Larkspur and other. By G. H. Clover (U. S.A. 

 Exp. Stn. Colorado, Bull. 113 ; 8 plates ; June 1906).— A number of 

 weeds poisonous to cattle occurring in Colorado are mentioned, including 



Delphinium bicolor, D. Nelsonii, D. glaucum, D. elongatum, Zygadenus 

 venenosus, Cicuta occidentalis, Lupinus sericeus,Aconitum columbianum, 

 and Hymenoxys floribunda. — F. J. C. 



Polygala apopetala. By T. A. Sprague (Bot. Mag. tab. 8065).— 

 Lower California. Nat. ord. Polygalaceae. Shrub or tree from 2-15 feet 

 high. Leaves lanceolate, 1^-3 inches long ; flowers about 1 inch across, 

 purple. — G. H. 



Poplar and Willow Borer. By W. J. Schoene (U.S.A. Exp. Stn. 

 Geneva, Bull. 286 ; 6 plates ; February 1907). — A beetle (Cryptorhynchus 

 lapathi L.) which has been introduced from Europe (and which occurs 

 in England) has been doing much damage to nursery stock and basket 

 willows, and now threatens ornamental poplars and willows. The 

 eggs hatch about September, and the larva bores into the tree and feeds 

 near the cambium, later penetrating more deeply into the tree. It is 

 whitish and shining, and is ready to pupate about the beginning of 

 July, the pupal stage lasting about fourteen days. The adult beetle is 

 about ^ to $ inch long, dull black with white scales here and there on 

 the body. The female eats holes in bark in which to deposit her eggs, 

 and this gives an opportunity of destroying the pest by spraying with 

 arsenical poisons, taking care to wet the twigs as well as the trunk. 

 Infested trees or portions of trees should be burnt, and young planta- 

 tions should not be made near old ones. — F. J. C. 



Potato Diseases. By T. W. Kirk, F.L.S. (Dep. Agr. N.Z. No. 7 ; 

 with 6 plates ; October 1905). — This bulletin includes reference to all 

 the potato diseases of New Zealand, viz. (1) Irish blight, Phytophtliora 

 infestans ; (2) early blight, Macrosporium solani ; (3) bacteriosis, 

 Bacillus solanacearum ; (4) scab, Corpora sca,bies ; (5) dry rot, 



