39 



two classes, active and resting. Active buds are growing or develop- 

 ing buds, such as one finds in late summer prior to the period of 

 rest and early in spring when tlie resting buds have been awakened 

 from their winter's slumbers. The resting buds are commonly known 

 as tointer buds (Plate ITT). 



Buds are protected growing points. The degree of protection 

 given to the growing points varies with the species. A few of our 

 trees and shrubs have buds which are nearly or quite destitute of a 

 scaly covering. These are know as naked buds. The protection 

 usually consi.sts of scales which may be supplemented by hairy out- 

 growths, resin, gums, or air spaces. Tliese are known as scaly buds. 

 The buds may be covered by numerous overlapping scales, known 

 as imbricated bud-scales, or they may be covered by simply one or 

 two visible .scales which do not overlap. The buds of the Willows 

 and Bultonwood are covered by a single visible bud-scale, while the 

 buds of such .species as the Striped Jfaple and the Black Alder have 

 only two visible bud-scales whose margins simply meet and do not 

 overlap. The latter are known as valvate buds. The buds may also 

 receive protection from the enlarged bases of the stalk of leaves 

 which often persist far into winter. The buds covered by the en- 

 larged base of the leaf-stalk are known as subpetiolar buds. The 

 buds of some of our common trees are very inconspicuous. It is 

 often difficult to locate them when sunken so deeply into the bark 

 that only the tip is visible. The size of the buds is not indicative 

 of the size of the flowers or leaves wliich they will produce the fol- 

 lowing .season. Many of tlie trees wliich bear small and inconspicuous 

 buds produce large and conspicuous flowers and leaves. The prin- 

 cipal functions of the jjrotcctive covering of buds are the prevention 

 of tlie loss of water from the tender parts within and the protec- 

 tion of their delicate interior from mechanical- injury. Some add 

 that the protection also minimizes the damaging efTect of sudden 

 temperature changes. 



The position of buds is of considerable value in distinguishing 

 many of our trees and shrubs. They may occur at the end of the 

 twigs or along their sides. The former are known as terminal buds 

 and the latter as lateral buds. The terminal buds may be solitary 

 as on the Beech or clustered as on the Oaks. On most of our trees 

 and shrubs the lateral buds appear just above the origins of leaf- 

 stalks and are known as axillary buds. They may occur in pairs, 

 one on one side of the twig and the other exactly opposite, or 

 singly forming a spiral around the twig. The former are known as 

 opposite buds and the latter as alternate buds. The axillary buds 

 may occur solitarj- or in groups, either one above the other, or side 

 by side. If they occur one above the other they are known as super- 

 posed buds and if they occur side by side they are known as accessory 



