NOTES AND ABSTRACTS. 



dry-rot of the potato tuber starting from the outside and due to the 

 fungus Fusarium trichothecioides Wollenw. The trouble appeared to 

 be most frequent where the tubers were not stored until they had 

 been out of the earth for some time. — F, J. C. 



Potato, The Tuber-Unit Method of Seed Improvement. By W. 



Stuart (U.S.A. Dep. Agr., Bur. PI. Ind., Circ. 113 ; Feb. 1913 ; 

 pp. 25-31 ; 2 figs.). — ^The average yields per acre in Great Britain 

 and Germany from 1901 to 1910 were 2007 and 200*8 bushels respec- 

 tively and in the United States 927 only, and the writer attributes 

 this in part to the care exercised by the European grower in the 

 selection of his seed supply. The most valuable feature of the method 

 recommended consists in the elimination of unproductive and diseased 

 plants rather than in the isolation of highly productive strains. Tubers 

 weighing from 6 to 8 ounces are recommended for planting, these 

 being cut into four. A careful study of strong and weak tuber units 

 of twelve varieties during two seasons shows the average production 

 of merchantable tubers from the strong plants to have been sixteen 

 times greater than that from the weak ones. — A. P. 



Potato Tuber, Dry-rot of the Irish. By E. M. Wilcox, 

 G. K. K. Link, and V. W. Pool [U.S.A. Exp. Stn., Nebraska, Research 

 Bull. I, and Bull. 134 ; March 1913 ; figs.). — A new species of 

 Fusarium, called by the authors F. tuberivorum, is found to cause 

 winter rot of potatos in the store. No other part of the plant can 

 be infected by the fungus, and infection of the tuber is only through 

 wounds (not through lenticels, eyes, or scab spots). Treatment of 

 potatos by immersion in formalin (i pint to a barrel of water) for two 

 hours and then drying, subjection to formaldehyde vapour (generated 

 by placing 23 oz. potassium permanganate in 3 pints of formahn 

 for treatment of 1000 c. ft.), and the 5-5-15 lime-sulphur wash were 

 found to reduce the amount of rot in a very marked fashion. A 

 considerable part of the bulletin is occupied by an account of the 

 structure of the fungus and comparison with allied species. The 

 second bulletin quoted is a popular edition of the first. — F. J. C. 



Potentilla Clusiana. By Reginald Farrer [Garden, Jan. 4, 1913, 

 p. 10). — ^A snow-white counterpart of P. nitida seems almost 

 unknown. It is a species of the Eastern limestones, where it replaces 

 P. nitida at considerable elevations on cliffs and rocky ridges. It is 

 woody-rooted, and, though impossible to collect entire, the broken-off 

 cushion can easily be made to root as cuttings. Its beauty and value 

 are enhanced by its flowering in late summer, when almost everything 

 but the Campanulas has gone to seed. — H. R. D. 



Precocious Flowering. By Dr. E. Goeze [Beth. Bot. Cent. xxx. 

 Abt. I, Heft I, pp. 114-121). — In general the age at which a plant 

 flowers is a specific character. Dry conditions, dry soil and air, and 

 a change in nourishment favour flowering. Moist or wet conditions, 



