'230 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



It is at all events important to remember that at this time the pest is 

 reduced to a minimum." 



So far, spraying has been found of no avail against this pest. It is 

 hoped, however, that the treatment suggested under 4 may be carried out, 

 but it seems scarcely possible that this method could clear the plants of 

 mites when the complete cutting down of extensive plots of infested 

 bushes has so completely failed even to check the increase of the mites. 



R. N. 



Branches. 



Branching' in Tropical Woody Plants. " Ueber die Ver- 

 zweigung." By M. Raciborski (Ann. Jard. Bot. Buit. vol. xvii. p. 1 ; 

 31 woodcuts ; 1900). — Concerning the growth and branching of woody 

 plants in Java Raciborski has brought together a number of interest- 

 ing facts, some new and some already known. He discusses in greater 

 detail the periodicity shown in the production of branches, the angular 

 divergence and length of successive branches. 



In many respects woody plants growing in the perpetually humid 

 tropical climate display in their growth likenesses to our own trees and 

 shrubs ; and in no case is this more marked than in the arrangement of 

 the leaves along the stems, the leaves formed at the commencement and 

 conclusion of the period of growth often being closer together than those 

 formed in the middle of the same period. Other examples show further 

 analogy in the production of foliage-leaves and scale-leaves ; but most 

 interesting are the cases described in which the close of the period of 

 growth is heralded by the production of smaller opposite foliage-leaves 

 (not scales) in place of the normal alternate foliage-leaves. 



In reference to the periodicity in the production of branches it is 

 pointed out that three types occur : (1) that in which the branches are 

 less numerous than the leaves on the same stem, because some buds 

 remain dormant ; (2) that in which the number of branches is equal to 

 the number of branches on the same stem, because one axillary bud 

 shoots out from the axil of every leaf (e.g. shoots of coffee and man- 

 gosteen) ; (3) that in which the branches on a stem are more numerous 

 than the leaves, because accessory buds shoot forth from the leaf-axils. 



The exceeding regularity of the arrangement of the successive 

 branches in reference to one another and to the leaves is illustrated by 

 various examples. For instance, in the jujube tree on certain shoots 

 one leaf subtending a branch is succeeded by two leaves without axillary 

 branches, upon which follows another leaf with an axillary branch, then 

 two without, and so on. A similar arrangement occurs in the rubiaceous 

 Randia long ispi Ha, which however has opposite leaves, in that one 

 branch-bearing node is succeeded by two branchless nodes ; on the 

 horizontal long shoots foliaged branches are replaced by axillary spines. 

 The climbing Randia scandens has decussate leaves, spineless long 

 shoots, and spine-bearing dwarf shoots ; on it two successive branch- 

 bearing nodes are regularly succeeded by two branchless nodes. 



In the last two sections of the paper it is shown that various types of 

 cvi nose inflorescence are simulated by racemose monopodial or cymose 

 sympodial systems of vegetative branches. For instance, in a species of 



