A BUD AND TWIG KEY. 

 By O. L. Sponsler. 



There is need of a compilation of descriptions of buds and 

 twigs which will include only the more important forest trees, 

 and will serve as a basis for a study of twig characters. An 

 attempt is made in this article to fulfill this want. The data 

 was collected from various sources and was found to be a mass 

 of incomplete descriptions. They were checked up with live 

 material whenever possible and often made more complete by 

 addition of greater detail. The material was arranged in key 

 form because that arrangement affords an easy means of com- 

 parison and gives prominence to the distinguishing features. It 

 is anticipated that as a key it will not be of especial value. The 

 work will be revised at a later date and will include a few more 

 species and complete descriptions. 



All the distinguishing features mentioned are visible with 

 the unaided eye or with a hand lens of about four diameters 

 magnification. The larger divisions of the key are based, 

 wherever possible, upon characteristics which first attract the 

 naked eye. In some cases the sub-divisions are based upon the 

 size of the bud or the twig, or upon the amount of pubescence 

 present. Such distinctions are often variable and unreliable but 

 serve to show a possible difference. 



Most of the terms used are common in systematic botany 

 or are self-explanatory. A few however need explanation. 



Tip-scar, a term used to designate the scar left when the de- 

 ciduous tip of the twig is cast off. This occurs in twigs 

 of indefinite growth. A few genera have formed the habit 

 of casting the end of the twig in early summer and allow- 

 ing the growth of the next season to be continued through 

 the uppermost lateral bud.* The scar thus formed is often 

 minute and indistinct as on the Hackberry, or very promi- 

 nent as on the Catalpa. 



Twig, the growth of the previous season only. 



Terminal bud, a term used to designate the bud at the end of 

 the twig when the seasons growth is definite, and when the 

 twig has no deciduous tip. 



*"Twigs of woody Plants", A. S. Hitchcock, The Plant world, Vol. 

 9, No. 1, January, 1909. 



