Pterocarya 439 



Fruit ^ inch broad ; wings semi-orbicular, concave below, conspicuously veined ; 

 nutlet with beaked apex. 



Seedling} — The caulicle terete, erect, and about two inches in length, raises the 

 two cotyledons well above the ground. Each cotyledon is shortly stalked, about an 

 inch in width, and deeply bipartite, the two primary divisions being again divided 

 for nearly two-thirds of their length, the whole forming four linear-oblong obtuse 

 diverging segments. The cotyledons are palmately five-nerved at the base, the 

 three middle nerves each ending at the base of a sinus and sending divisions into 

 the segments. The young stem is slightly glandular near the apex. The first five 

 leaves are alternate, simple, lanceolate or ovate, rounded at the base, acute or 

 acuminate at the apex, penni-nerved, serrate, and vary in length from i to 2 

 inches. Succeeding leaves are compound, unequally pinnate, and with many 

 leaflets. 



Identification 



In summer this tree is only liable to be confused with Pterocarya rhoifolia, 

 which has scaly buds. It is distinguished from all species of Juglans by its 

 naked buds. 



In winter the following characters are available: — Twigs stout, olive green, 

 glabrous except at the minutely pubescent, glandular tip. Leaf-scars oblique on 

 the twigs, their lower part projecting, large, obcordate, marked by three crescentic 

 prominences, which are the fused cicatrices of the vascular bundles. Pith pentagonal 

 in cross section, chambered in longitudinal section. Buds without covering scales, 

 consisting of a short shoot and three to four undeveloped leaves, which are stalked 

 below, enlarged and lobed above, rusty brown in colour, minutely pubescent and 

 glandular. Lateral buds multiple, two to three superposed vertically above each 

 leaf-scar ; the uppermost one like the terminal bud, but smaller and stalked ; the 

 lowermost close to the upper margin of the leaf-scar, minute and rudimentary. 



Variety and Hybrid 



1. Var. dtimosa, Schneider, Laubholzkunde, 94 (1904); Pterocarya dumosa, 

 Lavallee, Arb. Segrez. 217 (1877). This is a shrubby form, with yellowish brown 

 twigs, and small closely-set leaflets, about 2^ inches long. The fruit and flowers 

 are unknown ; but it is probably a horticultural variety of P. caucasica. 



2. Pterocarya Rekderiana, Schneider, op. cit. 93. This is a hybrid between 

 P. caucasica and P. stenoptera, which was described by Rehder in Mitth. Deut. 

 Dendrol. Gesell. 1903, p. 116. It grows in the arboretum at Segrez; and plants of 

 it are now cultivated in the Arnold Arboretum," Massachusetts, where it is perfectly 

 hardy. It is intermediate in character between the two species. The leaflets in 

 texture, serration, etc., resemble those of P. caticasica, being a trifle smaller ; but 



' Cf. Lubbock, Seedli)igs, ii. 521, fig. 662 (1S92) 



'^ Two seedlings were raised by Elwes from seeds of this tree, one of wliich is now about eigliteen inches high, and shows 

 evidence of its hybrid origin in the leaves. 



