NOTES AND ABSTRACTS. 



513 



which is the only variety of pear grown in any quantity in Cahfornia. 

 The ' Le Conte ' stock strikes freely from cuttings, produces a stem 

 free from suckers and shoots, and is almost immune. The seedling 

 stock has the two vital defects of suckering freely and being suscep- 

 tible to the bhght. 



The remedies suggested for walnut blight in California are on the 

 same lines — namely, careful cultivation and the use of disease-resisting 

 stocks, California black walnut, Juglans Hindsii (N. California), and 

 Juglans californica (S. California). 



The best varieties are * Eureka,' ' Concord,' ' Chase,' ' San Jose,' 

 and the French varieties, ' Tranguette ' and ' Mayette. ' 



The dying back of apricot fruit-buds has been found to be due 

 to Coryneum Beyerinckii (the peach-blight fungus), and the black spots 

 on the fruit, which cause it to split, is Cladosporiuyji carpopliyllum. 



In the case of apple mildew the best results were obtained by 

 spraying with sulphides or surphur-containing sprays in spring and 

 early summer. 



Whole plantations of tomatos are reported to have been completely 

 ruined in 1907 by Phytoplitlwra injestans. Bordeaux mixture after 

 rain was found to be the most effective remedy. — D. M. C. 



Plantae StrauSSianae. By Dr. J. BornmiiUer [Beili. Bot. Ce7it. 

 sxvi. 2. Abt. Heft ih. pp. 434-444; 1910).— The description of the 

 plants collected by Th. Strauss in "West Persia in the years 1889-1899 

 is here completed. This contribution contains the Cyperaceae, 

 Graminaceae, Coniferae, Gnetaceae, Filices, and Et^uisetaceae, with 

 a list of localities and index. — G. F. S.-E. 



Plum Aphis, The SouthePn (Aphis sectariae, Thos.) By C. E. 

 Sanborn {U.S.A. Exp. Stn., Oklahoma, Bull 88; Mch. 1910; 5 figs.).— 

 The wingless aphis, which begins the atliack on the plum in the spring, 

 is known as the " stem mother," and hatches from an egg deposited 

 the previous autumn. This " stem mother " can produce young at the 

 rate of two to five a day for a period of four weeks. The young grow 

 quickly and reproduce rapidly, and winged forms develop which fly 

 to other trees, there to establish fresh colonies. 



When the terminal branches of the tree have finished growing and 

 the leaves are toughened with age the aphides leave the trees and 

 establish wingless colonies on certain grasses growing in the locality. 

 From this wingless form winged * ' migrants ' ' arise at the fall of the year 

 which travel to the plum trees and found new colonies in the spring. 



Autumn spraying with lime-sulphur is recommended for destroying 

 the eggs, and as a summer remedy tobacco- water. — -V. G. J. 



Pollen, Some Conditions which Influence the Germination 

 and Fertility of. By E. P. Sandsten {U.S.A. Exp. St7i. Wisco7isi7i, 

 Research Bull. 4, June 1909; 5 figs.). — The author found that ripe 

 pollen of apples, pears, and plums was not greatly injured by a tem- 



