32 BUDS ON STEMS. 



the first year and those which remain dormant until called upon to replace the 

 earlier ones originate all together simultaneously. In the Common Elder (Samhucus 

 nigra) two buds are formed one above the other in each leaf-axil; in the blue- 

 berried Honeysuckle (Lonicera ccerulea) and in several of its allied species, three 

 buds of almost equal size are superimposed one above another in a straight line in 

 each axil. In the year following their formation, usually only one of them grows 

 out into a shoot; the others stop as they are, and maintain their vitality for a 

 couple of years in reserve and only then develop if the first shoot has met with 

 destruction. The North-American False Indigo, species of which (e.g. Äviorpha 

 fruticosa, A. glauca, and A. nana) are cultivated as ornamental shrubs in European 

 gardens, produces two buds of different sizes above each foliage-leaf, the larger of 

 the two being placed just above the smaller. The former sends forth a shoot in the 

 following year, the latter remains in reserve. If the shoot first developed withers, 

 as very often happens, the reserve-bud sprouts, and the withered stump of the 

 first shoot is then visible just above the fresh one. The North-American tree 

 Gymnocladus Canadensis also exhibits on the upper ramifications of its powerful 

 branches two superimposed buds above the insertion of each leaf; the larger is 

 situated above the smaller, and the latter only develops into a shoot in the event of 

 its being required as a substitute. Several other woody plants which, though their 

 stems become very thick, possess neither the growth of a tree nor a symmetrical 

 crown of foliage — such as the Judas-tree (Cercis Siliquastrum) and the Forsythia 

 viridissima of Japan — put forth long switch-like shoots, the upper halves of 

 which often die off" during the winter. The buds on the lower surviving half 

 of each shoot are very close together, and generally they are in pairs, the upper 

 one in each pair being close upon the lower. Only the upper one of a pair is at 

 first developed in the next year; the lower bud does not develop unless the other 

 fails. 



It is sometimes the case that the axil of every leaf produces three buds set side 

 by side instead of one above another. The middle bud sends out a shoot in the 

 following year whilst the lateral ones are left as a reserve. The year after, if the 

 shoot has died, what happens is either that one of the two accessory buds develops — 

 as, for example, in Lonicera fragrantissima and in the case of the long shoots of 

 the Nettle-trees (Celtis Toitrnefortii, C. orientalis, C. occidentalis), or both accessory 

 buds develop simultaneously — as in the Southern Reed (Arundo Donax) and in 

 several species of the genus Bambusa. Thjd species belonging to the genus Zan- 

 thoxylon form in each leaf-axil the rudiments of from nine to eighteen buds, of 

 which the middle one is the biggest and grows out during the following year into a 

 short or long shoot. The other smaller buds are kept in reserve in the cortex at 

 the base of the shoot. 



In the Tree of Chastity ( Vitex Agnus-castus) four buds are set in the axil of 

 each foliage-leaf. The central bud is the largest and a smaller one is situated under- 

 neath it, whilst the other two — also smaller — are posted to the right and left respec- 

 tively of the first. Next year a shoot is put forth from the large central bud whilst 



