484 JOURNATj of the royal HORTTCVil/rrRAL SOCTRTY 



Among the new hybrids of Philadelphus are: 'Avalanche,' 

 ' Bouquet blanc, ' ' Conquete,' erecUis, ' Fantaisie,' fimhriahis, ' Gerbe 

 de Neige,' ' Manteau d'hermine,' ' Mer de glace,' 'Mont-Blanc,' 

 ' Nu^e blanche,' 'Pavilion blanc,' p7irpureo-maculatus , ' Eosace,' 

 ' Virginal.' — F. A. W. 



Dionaea, Closing' of Leaves of. By W. H. Brown and L. W. 

 Sharp {Bot. Gaz. vol. xlix. pp. 290-302; April 1910).— The authors 

 find that it is the intensity rather than the number of stimuli which 

 induce closing. The number of stimuli required varies in the inverse 

 order of their intensity. Eesponse is brought about by the compression 

 of the cells, not only of those at the base of the hairs, but also of 

 other cells of the leaf -blade. Contact with a hard object, continued 

 pressure, or release of pressure does not produce closing. 



Water at the temperature of the room only causes closure when it 

 bends a sensitive hair. In other respects their experiments seem to 

 confirm those of Macfarlane and others. — G. F. S.-E. 



Disease-resistant Plants, Development of. By G. M. Eeed 



{II. Ann. Rej). Missouri State Bd. of Hort., 1908, p. 284).— Eelates 

 successful experiments in selecting for seed parents disease-resisting 

 specimens, and raising hybrids, one parent being disease-resistant, 

 and attributes resistance to chemical rather than anatomical differences 

 in plants. — E. A. B. 



DropWatering* (Le Jard., vol. xxiii., No. 543, p. 302; Oct. 5, 

 1909). — A new method of watering has been invented by Dr. A. Koren, 

 which is explained at length in the Annates de la Direction de 

 VHydraulique et les ameliorations agricoles. It is said to increase 

 production in fruit gardens to the extent of 650 per cent. The 

 water is led from the reservoir to the garden by a long conduit at 

 a certain height above the ground, whence it is distributed to zinc 

 receivers 4 metres long and 0*75 m. wide, perforated like a rose and 

 placed on each side the conduit. These receivers run on wheels, and 

 can be moved from one place to another. They are fed by means of 

 zinc funnels with rubber tubes, which are dropped into the conduit near 

 the receivers. The watering then takes place mechanically. When 

 one part is sufficiently irrigated, the gardener rolls the apparatus on to 

 the next, with no need for personal supervision. The holes of the rose 

 contain little balls which prevent the water from flowing out in too 

 heavy a jet, to the injury of the germinating seeds and seedlings. This 

 method further has the advantage of warming the water, which is 

 exposed to sun and air in the conduit receivers, and has been found 

 to rise from 15° to 30° 0. in its passage from source to soil under these 

 conditions. A movable gutter of perforated zinc connected with the 

 rain-water tank would roughly give the same results. — F. A. W. 



Economic Plants, Distribution of, from W.I. Botanic Sta- 

 tions {West Indian Bull. vol. x. No. 2, pp. 146-152 ; 1909).^The West 



