JUGLANDAOEAE. 



19 



PTEROOAEYA. 

 (Family Juglandaceae). 



Trees: deciduous. Twigs moder- 

 ate or rather stout, rounded: pith 

 moderate, angular, chambered 

 with rather close thin light brown 

 plates. Buds rather large, super- 

 posed, the upper distinctly stalked 

 or elongating the first year, naked, 

 with folded leaves. Leaf-scars 

 alternate, elliptical or 3-lobed, 

 large, rather low: bundle-traces 3, 

 crescent- pr horseshoe-shaped, cre- 

 nated or fragmented: stipule- 

 scars lacking. 



Winter-characters of Juglanda- 

 ceae are discussed by de Candolle 

 in his classic memoir on the fam- 

 ily published in volume 18 of the 

 fourth series of the botanical sec- 

 tion of the Annales des Sciences 

 Naturelles, in 1862; and are shown 

 in Michaux' Sylva. 



References to Pterocarya: P. fraxinifolia. Leavitt, Out- 

 lines of Botany, 31, f. 22; Schneider, f. 5, 86. P. rhoifolia. 

 Leavitt, Outlines of Botany, 29, f. 18; Shirasawa, 232, pi. 1. 

 P. stenoptera. Schneider, f. 86. 



Like the other Juglandaceae, and particularly Juglans, 

 Pterocarya well illustrates distinct superposed buds, of which 

 the uppermost is largest. This is the usual condition in such 

 cases. 



1. Twigs distinctly pubescent and glandular. P. stenoptera. 

 Twigs essentially glabrous and glandless. 2. 



2. Twigs and buds red-brown. (1). P. fraxinifolia. 

 Twigs and buds gray-brown. P. rhoifolia. 



