72 BUDS AND STIPULES 



In other cases the leaves form successively a more 

 or less complete covering for those that follow, as, for 

 instance, in the St. John's Wort (Hypericum) (figs. 

 107, 108). 



In the Common Barberry (Berb&ris vulgaris) (fig. 

 109) the primary leaves are changed into spines. 

 The bud, however, in the axils of these spinose leaves 

 develops into a short axis with. 



,, |j foliage leaves. This is why 



the leaves in this species are 

 collected in tufts. 



In Azima tetracantha (a 

 member of the Salvador acece, 

 a small tropical family of Di- 

 cotyledons) the axillary buds 

 are rather remarkable. What 



FIG. 109.-Sn OF BAR- a PP ear to be tw S P in6S 



BERRY (Berberis vulgaris), a ted in the axil of the leaf 



showing three spines, Sp, 



representing the leaf. Nat. are really the first pair of 



A, stem'; L , L) leaves on a lateral leaV6S f the Axillary shoot. 



SSfc^i^aS 6 ^^^ In their early stages they are 



red uced to short, subulate spines ; , , , . -. , 



L', L', more perfect leaves on the erect, closely applied, and very 



same lateral shoot. J 



short, but when fully developed 



they become hard, spiny, and diverging. Their foliar 

 nature is further indicated by the fact that a slender 

 groove runs along the opposing faces from apex to 

 base, where there is a deeper cavity, as if a sheath 

 were attempted. They are also articulated with the 



