NOTES AND ABSTRACTS. 



793 



Plums, Japanese. By Henry Dunsmore (U.S.A. Hort. Soc, 

 Minnesota, Trans. 1912 ; pp. 5-6). — The writer grew four varieties 

 of these for eight years without producing a single plum, owing to 

 the injury to the trees in winter. He grafted the Satsuma on a 

 head of Aitkin Plum in 1907, with the result that it has suffered 

 practically no injury, and in 191 1 produced a heavy crop of highly 

 coloured fruit, while the original tree from which the graft was taken 

 has continued to be cut back each winter. — A. P. 



Podachaenium eminens (Bot. Mag. tab. 8502). — Family Com- 

 positae, tribe Helianthoideae. Central America. Shrub ; leaves 

 ovate, up to 9 inches long. Corymbs terminal, leafy. Heads 

 inch across. Ray-florets white ; disk yellow. — G. H. 



Pollination of Fruit Trees and its Bearing on Planting. 



By C. H. Hooper (Gard. Chron. Dec. 6 and 13, 1913, pp. 393 and 420). 

 — A review of experiments by the author and Messrs. Chittenden 

 and W. Backhouse regarding the order of flowering, self -fertility or 

 sterility of Apples, Pears, Plums, and Cherries. Tests with smeared 

 microscope slides for wind dispersal of pollen and a comparative 

 table of the numbers and kinds of insect visitors. — E. A, B. 



Potato Scab, The Pathological Anatomy of. By F. Lutman 

 (Phytopathology, vol. iii. pp. 255-264, Oct. 1913 ; fig.). — The American 

 scab of potatos is now usually ascribed to the fungus Oospora scabies 

 Thaxter. There appears some doubt as to whether this is a true 

 fungus or a bacterium, but none that it acts upon the cork cambium, 

 stimulating it to hyperplasia and hypertrophy. The present paper 

 deals with the anatomy of the scab in various stages of its develop- 

 ment. The organism was not found in the cells of the potato, but 

 one similar in appearance and probably identical with Beijerinck's. 



Streptothrix chromogen has been seen many times in surface view 

 of the cork cells. The appearance of cells from under scab suggests 

 that they contain numerous minute bacteria, but the author shows 

 that this appearance is due, not to bacteria, but to very numerous and 

 minute oil globules in the cells. The presence of these bodies appears 

 to be one of the results of the disease, as starch is not contained in the 

 affected area. — F. J. C. 



Potato Tuber Moth (U.S.A. St. Com. Hort., Cal, Bull. 

 May 1912, vol. i. No. 6 ; 23 figs.). — The principal item in this paper 

 is a description of the Potato Tuber Moth (Phthoximaea opercella 

 Zeller) by E. O. Essig. The larvae of the moth mine the leaves, stems, 

 and tubers of potatos. In the fields, especially while the vines are 

 still green and growing, they work mostly within the leaves and stems. 

 The greatest damage, however, is done to the tubers just before, or 

 just after, they are dug. The moth deposits its eggs on the potatos, 

 and the larvae, hatching, immediately bore into the tubers at the eye 



