620 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



of the parasite ; and (3) the reaction of the host after occupation, and 

 the subsequent reciprocal action of host and parasite. The present paper 

 deals chiefly with the first of these stages. In infection two steps are 

 recognised — entry or inoculation and infection. Inoculation includes 

 the entry of the germ tube through the stomatal opening, and the 

 formation under the latter of the substomatal vesicle. Infection is the 

 production of infecting hyphae from the substomatal vesicle which apply 

 themselves closely to the internal cells of the host plant and send into 

 them their haustoria. Thus a plant may be inoculated by a fungus 

 spore, but infection may not follow. 



The author gives details of the histology of nine species of rusts and 

 sums up his results at the end in tabular form. He finds considerable 

 variation displayed by the germ-tube, appressorium, substomal vesicle 

 haustoria, and hyphae, but he shows at the same time that each set of 

 infection phenomena is of a very definite nature for each species of 

 uredo. — A. D. C. 



Saccolabium rubescens. By R. A. Rolfe (Bot. Mag. tab. 8121).— 

 Nat. ord. Orchidaceae ; tribe Vandeae ; Annam. Erect epiphyte, 1 foot 

 high ; flowers J inch long, light rose-purple ; spur \ inch long.— G. H. 



Salvia splendens * Surprise.' By G. T. Grignan (Bev. Hort. 

 June 16, 1907, pp. 279-281 ; coloured plate and 1 woodcut). — The plate 

 represents three Salvias, one of which, S. splendens, is of an extremely 

 vivid scarlet and very floriferous, while S. s. 1 Surprise ' is similar, with 

 pinnatifid, finely variegated leaves, centre yellow, edges green. — C. T. D. 



San Jose Scale. By. H. T. Fernald (U.S.A. Exp. Stn. Mass., 

 Bull. 116 ; March 1907). — An outline of the life-history of this pest and 

 the injuries caused by it, together with a summary of experimental work 

 in other stations. At this station a variety of caustic washes, crude 

 petroleum, emulsified kerosene, and lime-sulphur-salt wash have been 

 tried, and, all things considered, the last gave the best results. The crude 

 oil and kerosene emulsions killed the scale, but injury was caused to the 

 trees after a few sprayings. The chemical composition of the lime- 

 sulphur-salt spray is given as follows : — 



Substances 



Per cent, in 

 fresh wash 



Per cent, after 

 12 hours 



Per cent, after 

 120 hours 



Calcium monosulphide, CaS, and calcium hydro- 









sulphide, Ca(SH) 2 



25-30 





21-26 



Calcium polysulphides, CaS.„ CaS 4 , CaS 5 . 



3-5 





2-3 



Calcium hydrate, Ca(OH)., 



9 



8-5 



7 





1-8 



2-3 



2-8 





0 



1 



2 



Calcium tliiosulphate, CaS 2 0 3 .... 





0-5 



0-8 









02 



With the exception of the hydrate, carbonate, and sulphate, which have 

 no insecticidal value, each of the other compounds was tried separately. 

 The experiments were not conclusive, as they were not tried upon a 

 sufficiently extensive scale ; but the calcium monosulphide and calcium 

 sulphite failed to improve the condition of the trees, and the hydrosulphide 



