20 



XATURE STUDY REVIEW 



[9:1— Jan., 1913 



-tr. 



— sx 



W 



Figure 6. — Twig of 

 Carolina Poplar. sx — 

 Stipule Scar. p — Star- 

 shaped Pith. 



Figure T. — Twig of 

 lUitternut. tr — terminal 

 bud. ax — axillary bud. 

 sp — superposed accessory 

 bud. p — cnambered pith. 



F'IGURE S. — Twig of 

 Red Maple, ax — axillary 

 bud. cl — collateral acces- 

 sory bud. 



dX7-^--SC. 



F'lGURE 9. — Twig of 

 Mulberry, ax — last axil- 

 lary bud often mistaken 

 for a terminal bud. sc — 

 self-pruning scar left by 

 fall of real terminal bud 

 and tip of twig. 



scars may be arranged along the twig in two longitudinal rows 

 when they are said to be 2-rankcd, as in the mulberry (fig. 9), or 

 in several rows when they are more than 2-rankcd as in the Pop- 

 lars (fig. 6). 



The size and shape of leaf-scars are important factors in 

 identification. They may be very narrow as in the Pear and 

 their upper margins may be ilat or convex as in the Black Ash 

 or deeply notched as in the White Ash or form a band nearly 

 surrounding the bud as in the Sycamore. 



At the bases of the leaves of some species a pair of small 

 leaflets called stipules are regularly formed and leave, at the fall 

 of the leaf, more or less definite stipule-scars at either side of the 

 leaf-scar as shown in the Carolina Po])lar (fig. (\) . 



