122 JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



all at the same time, the flowers at the outer edge open more widely than 

 those of the centre ; the three flowers which terminate the cluster do not 

 expand at the same time, the most central flower expands at the same time 

 as the other flowers of the cluster, while the two which accompany it are 

 still in bud. Only a small number of flowers borne by a tree are destined 

 to give fruits ; most act as male flowers producing a considerable quantity 

 of pollen. If the flowers are thinned in the apple the lateral flowers 

 would be cut out, keeping the terminal ; if the terminal is missing, leave 

 two or three of the innermost. With the pear, on the contrary, the 

 central flowers would ba cut out and the lateral ones left. The number 

 of flowers left would be ruled by the variety, the varieties with small fruit 

 having the most flowers left. 



Photographs of pear inflorescences show two central flowers already 

 fallen, and the small flower at the extremity ready to fall, whilst two 

 outside fruits springing from the base of the cluster are well set. 



The photographs of apples show the central fruit larger, and stem 

 more fleshy, whilst those at the base, on the contrary, have thin stems 

 and fruit hardy formed. 



The hope is expressed that research will be made to find out which 

 varieties of Pears and Apples are the best suited as fertilizers (i.e. pollen 

 producers). — C. H. H. 



Insecticides— Nicotine, Lead Arsenate, and Paraffin Emulsion. 



By the Duke of Bedford, K.G., and Spencer U. Pickering, F.R.S. 

 (Woburn, Tenth Beport, 1909, pp. 35-42).— Further experiments were 

 made in continuation of those detailed in the Eighth Report (p. 83) to test 

 the comparative insecticidal effect of these three washes. Nicotine was 

 not successful with caterpillars generally, and quite inoperative against 

 the winter moth caterpillar, which was completely destroyed by paraffin 

 emulsion (solar distillate If per cent, emulsified with iron solution), as 

 was also the grub of the gooseberry and currant sawfly. The emulsion 

 was much more effective than lead arsenate and did not interfere with 

 the sale of the fruit, but it cannot be used while the trees are in blossom. 

 The experiments were mainly restricted to these two pests. Paraffin 

 emulsions are quite harmless if properly made, but the precaution of 

 churning them up again with a syringe should always be taken (pp. 43-46). 



A. P. 



Ipomoea mexicana grandiflora alba. By B. Chabaud (Rev. 

 Hort, December 1, 1908, pp. 552, 553). — From the description this Con- 

 volvulus is extremely attractive, the flowers being very large and sweetly 

 scented. It flowers, however, in the evening and fades early in the day ; 

 but as it flowers for a week after cutting, this drawback is largely dis- 

 counted. It is also known as the ' giant white Ipomoea.' — G. T. D. 



Iris germanica. By P. de Vilmorin {Jour. Soc. Nat, Hort Fr., 

 p. 653, November 1908). — A note on the parentage of the Iris germanica 

 as we know it and a description of some new varieties obtained by the 

 author.— M. L. H. 



Iris germanica macrantha. By Ph. de Vilmorin (Rev. Hort. 

 December 1, 1908, pp. 544, 545 ; coloured plate). — Two very beautiful 



