6 A Bud and Twig Key 



b2. Terminal buds one-quarter inch or shorter and nearly 

 as broad, one or two pair of scales visible, light or dark 

 brown felty, many bundle-scars form nearly a solid U-- 

 shaped line, twigs large, no stipule-scars, lateral buds 

 small globose, leaf -scars semi-orbicular or lunate. 



Fraxinus Linn. 



ci. Twigs four-angled or -winged, buds light brown, out- 

 er pair of scales with pinnate apex. Plate I. 



F. quadrangulata Michx. 



C2. Twigs cylindrical, pubescent or glabrous, buds dark 

 brown, scales broad ovate, apex acute. Plate I. 



* F. americana Linn. 



* F. pennsylvanica Marsh. 



* F. lanceolata Borkh. 



* F. oregona Nutt. 



* F: nigra Marsh. 



b$. Terminal bud one-quarter inch long, several smooth red 

 scales, distinct stipular line connects leaf-scars, bundle- 

 scars five to seven distinct, twig large glabrous green 

 changing to red during winter, leaf-scars crescent- 

 shaped. Acer macro phyllum Pursh. 

 aj. Bundle-scars many forming an ellipse. 



Catalpa (see above, page 4). 



///. Leaf-scars alternate, one at each node. 



ai. Bud at end of twig entirely or partially sunk in bark. 

 bi. Twigs armed with two stipular prickles, bundle-scars 

 three, buds white silky hidden beneath shield-shaped 

 leaf-scar, no terminal bud, tip-scar or dead tip of the 

 twig prominent, twig reddish brown. 



Robinid pseudacada Linn. 



* It is difficult to distinguish between these species without leaves and 

 fruit. A cross-section of the terminal bud of F. nigra is usually elliptical 

 and shows three pair of bud-scales, while in the case of the other four 

 species of the cross-section is more or less four-lobed and usually shows 

 four scales. In the East the twigs of F. pennsylvanica are pubescent and 

 the buds small, while F. americana and F. lanceolata are glabrous and the 

 buds large, but near the Mississippi River and west of it there is much 

 Confusion of these three species. The twig of F. oregona is often light 

 woolly. 



