154 TKANSACTIONS AND PROCEEDINGS OF THE [Sess. i.xiii. 



On Interfoliar Buds in Pines. 



By A. W. BoRTHWiCK, B.Sc. 



(Read 12th Jaimaiy 1800.) 



The bud which represents the future shoot is found in 

 very various stages of development, according to the species 

 of plant to which it belongs. In many cases it consists 

 merely of a papilla of cells, and will develop only under 

 certain conditions. The winter buds of our trees and 

 shrubs are more or less highly developed, but it is among 

 the conifers that we find the two extremes. The one 

 extreme — the highest development — is found in the end 

 and whorl buds of -pines. There all the leaves are 

 metamorphosed into dry scales, and their axillary buds are 

 so highly differentiated that the foliar spurs may be 

 recognised. The other extreme — the lowest development 

 — is seen in the winter buds of Abies and Ficea, where the 

 future shoot is represented merely by a green, fleshy 

 tubercle, bearing on its surface small papilla-, which are 

 the leaf rudiments. In order to protect this bud, the apex 

 of last year's shoot is swollen out, and the needles belong- 

 ing to it are changed to scales, which cover tlie real bud 

 like a cap. 



The pine tree possesses the following kinds of buds : — 

 (1) apical buds ; (2) whorl buds — (a) such as produce 

 whorl branches, (b) such as produce female flowers, (c) 

 dormant buds, or cryptoblasts, whicli develop after severe 

 damage to the leaves, etc. ; (o) interfoliar buds, or 

 brachyoblasts ; (4) axillary buds in the axils of primary 

 leaves in the young plant (such buds become functionless 

 after the fifth year, when bark formation begins) ; lastly, 

 primary leaf axil-buds on young shoots, whicli produce 

 male flowers. 



The a])ical and whorl l)uds, or macroblasts, 1 have 

 already briefly described, and will now pass on to consider 

 the occurrence, structure, and function of dormant buds or 

 cryptoljlasts. 



Itcgularly one or two of the whorl buds remain dormant, 

 that is, do not shoot out the year after their formation. 

 Some authorities liold tliat doiniant Ijuds occur only on 

 very old trees, and will dcvcloj) only after the tree has 



