SUMMER KEY TO THE SPECIES OF JUGLANS 



a. Leaflets 11-17, the terminal usually present; pith of twigs 

 chocolate-brown; bark of trunk rather smooth, or fissured, 

 with broad, flat, whitish ridges; fruit elongated, sticky- 

 downy J. cinerea, p. 63. 



aa. Leaflets 13-23, the terminal often lacking; pith of twigs 

 cream colored; bark of trunk rough, brownis-h or blackish, 

 deeply furrowed by broad, rounded ridges ; fruit globose, not 

 sticky-downy /. nigra, p. 65. 



60- 



