﻿48 The New York State College of Forestry 



I. As to position — Continued 



d. Subpetiolar. Buds which burst through leaf-scars or 

 are enclosed in the holloAA^ base of a leaf stalk and 

 become visible only after leaf-fall. (Fig:. 68.) 



II. As to covering. 



a. Scaly. Protected by scales which are valvate or over- 



lap. 



1. Laminar. When the bud-scales are modified leaf- 



blades (laminae). (Fig. 76.) 



2. Petiolar. When the bud-scales are modified (flat- 



tened) leaf -stalks (petioles). (Fig. 77.) 



3. Stipular. When the bud-scales are modified 



stipules. (Fig. 75.) 



b. Naked. Devoid of scales, usually protected by hairs 



or down or by being sunk in the cortex. 



The ideal time to study bud coverings is in the spring at the 

 time of the inception of the new growth. Transition stages 

 between typical leaf-parts and typical scales are often visible 

 which indicate beyond question the origin of bud scales. 



It follows that stipular bud scales are always found in 

 pairs. Laminar and petiolar scales, inasmuch as they are leaf- 

 parts proper, follow phyllotaxy. Plants with alternate leaves have 

 alternate bud-scales of either of these types and the same applies to 

 opposite-leaved plants. The number of bud-scales to a bud 

 varies widely in different plants, but is fairly constant within 

 the species. 



III. As to contents. 



a. Leaf-buds. Buds containing only the rudiments of 



leaves. 



b. Flower-buds. Buds containing only the rudiments of 



flowers or inflorescences. 



c. Mixed buds. Buds containing the rudiments of both 



leaves and flowers. 



IV. As to dormancy. 



a. Active. Buds which develoji the spring following 



their formation. Usually toward the top of the 

 growth of the season. 



b. Dormant. Buds which remain dormant except under 



the stress of exceptional conditions such as defolia- 

 tion. Usually near the base of the groAvth of the 

 season. 



