NOTES AND ABSTRACTS. 



495 



Quack-grass, The Eradication of. By J. S. Cates (U.S.A. Dep. 

 Agr., Farm. Bull. 464 ; Aug. 1911 ; 6 figs.). — Agropyron repens (twitch 

 or couch grass) is prevalent in the North Central and North-Eastern 

 States, and a number of closely allied species in the Rocky Mountains 

 and the Pacific States. It is believed that the principles laid down 

 in this bulletin apply equally well to all rootstock-producing species 

 of the same genus. — A. P. 



Radamaea (Bentham) and Nesogenes (A. de Candolle), On the 

 Genera. By W. Botting Hemsley, F.R.S., F.L.S., V.M.H. (Jour. 

 Linn. Soc. vol. xli. No. 282, pp. 311-316; July 1913; with 1 plate). — 

 This paper gives an historical account of the discovery of several 

 species of Nesogenes and a systematic description of their principal 

 morphological features. 



Radamaea prostrata (Bentham) is shown to be more correctly 

 referred to the genus Nesogenes. 



The genus Nesogenes is restricted to coral islands, or coral forma- 

 tion, in two very distant, relatively small areas within the southern 

 tropic ; the one in the Pacific Ocean with a median longitude of 

 about 145 0 W. ; the other in the Indian Ocean with a median longi- 

 tude of about 6o° E. It is not unlikely that intermediate stations 

 may be discovered, but it is also possible that the present widely 

 separated stations may have resulted from the disappearance of 

 these plants from the intervening country owing to changes in the 

 physical conditions of these parts. — R. B. 



Raspberry and Loganberry, Diseases of (Jour. Bd. Agr. 

 vol. xix. No. 2, pp. 124-126 ; plate). — The diseases caused by the 

 two fungi Hendersonia rubi, Westendorp, and Ascochyta pallor, Berk., 

 are described, and preventive measures are suggested. — A. S. 



Remusatia, The Araceae-genus, in Cameroon. By A. Engler 

 (Not. Konig. Bot. Berlin, vol. v. No. 50, pp. 300-301 ; Jan. 1913). — 

 That genera and species of plants closely related to Indian ones have 

 been found in tropical Africa, and especially in the mountainous regions 

 in the east and central areas north of the Equator, is well known. 

 Now, however, an Indian plant-type has been found in the wooded 

 district of West Africa. This is Remusatia, found by C. Ledermann in 

 1909 in north-west Cameroon, growing as an epiphyte upon the fallen 

 trunk of a forest giant. The nearest station to this from which 

 Remusatia vivipara has been recorded is in the Himalayas west of 

 Nepal. Although the hooks upon the adventitious buds of this plant 

 enable these structures to cling to passing animals which can convey 

 them over long distances, yet the distance between Cameroon and 

 Himalaya is so great that we may assume that intermediate stations 

 for this plant will yet be discovered. — R. B. 



Rhizoctonia Diseases (Jour. Bd. Agr. vol. xx. No. 5, pp. 416- 

 419 ; plate). — The diseases caused by Rhizoctonia violacea, Tul., and 

 R. solani, Kuhn, are described, and preventive and remedial measures 

 are given. — A. S. 



