102 MISSOURI BOTANICAL GARDEN. 



Buds rather large (about 5 mm. long) : twigs relatively stout. 

 Twigs deep red, glossy : buds conical, acute, nearly black: leaf - 



scars often separated . • . . A. grandidentatum. 



Twigs reddish buff. 



Buds conical, acute, gray pubescent: twigs mostly glossy. 



A. saccharum. 



Buds conical ovoid, often obtuse, usually darker : twigs mostly 



dull: bark of trunk mostly dark A. saccharum var. barbatum. 



Twigs green to gray buff, dull. 



Buds ovoid-conical, often very obtuse : bark of trunk black. 



A, saccharum var. nigrum. 



Buds small (2 to 3 mm. long), globose-ovoid, usually very 

 obtuse : twigs very slender A. Floridanum. 



Group I. Bush Maples (Plate 14). 



Buds evidently stalked, with valvate scales. 



A. Pennsylvanicum L. (Striped Maple). — Shrub or 

 email tree. Bark rather thin, green brown or red with 

 narrow white longitudinal lines and often transversely 

 warty, or at length dark gray ; twigs relatively stout, gla- 

 brous except for a few brown hairs at the uppermost node, 

 green or red, without conspicuous lenticels; leaf scars 

 broad, with often five or seven bundle scars; buds red, 

 glossy, 6 to 10 mm. long exclusive of the rather long 

 stalk. — Canada to Minnesota, south to the mountains of 

 Georgia. 



A. glabrum Torrey (Dwarf Maple). — Shrub or small 

 bushy tree. Bark thin, gray to brown, smooth; twigs 

 glabrous, slender, mostly bright red, becoming white or 

 gray, with few small dark inconspicuous lenticels, their 



epidermis flaking off in a thin silvery film after which the 

 gray or buff and red coloration is more or less in reticulated 



scars 



5 



ump 



margined, mostly bright red, glabrous. — British 



Columbia 



mountains of New Mexico, Ari 



Nevada. 



A. spicatum Lam. (Mountain Maple). — Shrub or small 

 bushy tree. Bark very thin, reddish brown to dingy gray, 

 with buff lenticels, smooth or slightly furrowed; twigs 

 gray tomentose above, slender, greenish with one side 



15 



