PTEROCARYA 



Pterocarya, Kunth, Ann. Sc. Nat., sen I. ii. 345 (1824) , Bentham et Hooker, Gen. PI. iii. 399 

 (1880). 



Deciduous trees belonging to the order Juglandeae, with large, alternate, com- 

 pound, imparipinnate leaves ; leaflets serrate ; stipules absent. Buds scaly or 

 naked, the lateral ones often multiple, two to three in a vertical row above the 

 insertion of the leaf Pith chambered. Flowers moncEcious, numerous in long 

 pendent catkins. Male catkins usually several, arising singly in the leaf axils ; 

 in some species {caucasica, stenoptera) lateral on the preceding year's shoots, 

 with an occasional catkin on the current year's shoot ; in other species {rhoifolia, 

 Paliurus) all on the new shoots. Stamens nine to eighteen in several series 

 on the axis of a three- to six-lobed scale, to which a bract is adnate on the 

 back, the scale representing two bracteoles and one to four perianth segments. 

 Female catkins solitary, terminating the young shoot. Female flowers with a bract 

 and two bracteoles at the base ; perianth four-lobed, adnate to the ovary, which 

 contains one ovule, and is surmounted by a short style, divided above into two 

 papillose stigmatic divisions. Fruit catkins long, with numerous nut-like fruits, 

 which have in most species two lateral wings, in one species a single orbicular 

 wing all round, due to the enlarged bracteoles of the flower, the bract persisting little 

 changed at the base of the fruit. Nutlet, with a thin pericarp and a hardened 

 endocarp, the latter divided below into four imperfect cells, and containing one seed, 

 which is four-lobed below. Cotyledons bi-partite, each division being again deeply 

 divided, forming four linear segments ; carried above ground in germination. 



Pterocarya and Juglans have similar foliage, and agree in the chambered pith 

 of the twigs. They are readily distinguished when in fruit, that of Pterocarya being 

 always small and winged. When specimens in leaf only are obtainable, the best 

 mark of distinction lies in the buds, which in Pterocarya are either without scales or 

 are enclosed in a long conical beaked funnel-like covering, composed of membranous 

 scales differing in either case from the short buds of Juglans with two to three 

 external scales. 



Seven species of Pterocarya are known, occurring in Persia, the Caucasus, 

 China, Tonking, and Japan. A hybrid species has been obtained in cultivation, 

 which will be described under P. caucasica. The seven species which occur in the 

 wild state may be arranged as follows : 



436 



