Ch. IV, 4] 



DEVELOPMENT OE STE-MS 



137 



center shows very clearly the characteristic tapering stem, 

 with the series of leaves in all stages of development 

 (Fig. 90V 



Within the buds the leaves are arranged in various ways, 

 either overlapping, or each folded by itself on its midrib, or 

 inrolled from margins or tip. The arrange- 

 ments are called collectively verxatiox. and 

 have importance in descriptive taxonomy. 



The most prominent, and commonh- the 

 largest, buds are those which are tekmixal 

 on the main stems and branches, and which 

 continue the stem growth. ^lore abundant 

 are the axillirv buds which develop in the 

 upper angle between leaf and stem, and are 

 nearly as numerous as the leaves themselves, 

 at least in exogenous plants. The functional 

 reason for the usual occurrence of buds in this 

 position is found, no doubt, parth' in the near- 

 ness to the source of food indispensable for 

 their development, and partly in the favorable 

 structural opportunity to make connection 

 with the main stem in the gap left in the 

 fibro-vascular cylinder above the leaf base 

 (page 119). In a few plants, of which Tatarean 

 Honeysuckle and Red ^laple are examples 

 (Fig. 91), more than one bud occurs in each 

 axil, either side by side, or one above another, 

 the extra buds being called accessory. 

 Finallv, while in manv plants no buds other accessor}- buds ; 



" . , .,, " ■ 1 1 X }■ (After 



than terimnal or axillary occur, m others they Gray.) 

 develop in almost any position, especially at 

 some place of injury; and these so-called .udvextitious 

 BVDS produce the branches in irregular positions, as often 

 seen in Willows and some other woody plants. Xot all 

 irreg-ular liranching, however, results from adventitious 

 buds, for axillary buds often remain latent for years, becom- 



FiG. 91, —A 

 twig of Red 

 Maple, showing 



