PTELEA PTEROCARYA 261 



Var. MOLLIS, Torrey (P. mollis, Curtis}. Leaflets broader than in the 

 type, but its chief distinguishing characteristic is the dense permanent 

 covering of greyish down on the lower surface. 



Native of S. Canada and the eastern United States; introduced to 

 England in 1704. Ptelea trifoliata is one of the most distinct of hardy 

 trees, and it is interesting for its large crops of curious elm-like fruits 

 which often strew the ground in its neighbourhood throughout the winter, 

 the fleshy part of the wing having decayed and left the netted veins. 

 Very little of the seed is fertile in this country, but the tree is easily 

 increased by cuttings. The bark, leaves, and young fruits emit a strong 

 and aromatic scent when bruised, and the last have been suggested as 

 a substitute for hops because of their intense bitterness. The tree is 

 of picturesque habit, perfectly hardy, and appears to thrive in any well- 

 drained soil. The leaves die off yellow in autumn. 



P. BALDWINII, Torrey. Western Hop Tree. A deciduous shrub up to 20 ft. 

 high with trifoliolate leaves much smaller than those of P. trifoliata. Leaflets 

 1 1 to 2 5 ins. long, narrowly ovate or obovate, the terminal one the longest ; 

 very downy beneath. Flowers in small terminal corymbs. Fruit winged, \ in. 

 across. It differs from P. trifoliata in its narrower leaves, larger flowers, and 

 narrow wing to the fruit. Native of N. California ; introduced to Kew in 

 1893. Not so striking a plant as its Eastern ally. 



PTEROCARYA. WING-NUT. JUGLANDACE^E 



At present five of the seven species of Pterocarya known are in 

 cultivation. They are deciduous trees with large, alternate, pinnate 

 leaves and pithy young wood ; leaflets varying from five to twenty-seven, 

 toothed, more or less oblong. Flowers unisexual, both sexes borne on 

 the same tree but on different catkins ; male catkins about one-third the 

 length of the female ones. The fruit is a small nut, large numbers of 

 which are strung on slender spikes 8 to 20 ins. long. From its allies 

 in the same natural order the walnuts and hickories Pterocarya differs 

 in the curiously winged nuts, and from the latter in the chambered pith. 



In gardens the only species well known is the Caucasian one (of the 

 rest five come from China, one from Japan), and no handsomer pinnate- 

 leaved tree can be grown in our climate. The others also are handsome, 

 but they have not yet shown their qualities as ornamental trees in Britain. 

 All of them are moisture-lovers, and for their best development should 

 be planted in deep loam. Young plants making vigorous succulent 

 shoots are sometimes cut by winter cold, and even old trees are liable 

 to injury by late spring frosts. Seeds afford the best means of propaga- 

 tion ; some species produce suckers, and probably cuttings of the roots 

 might also be employed. 



P. CAUCASICA, C. A. Meyer. CAUCASIAN WlNG-NUT. 



(P. fraxinfolia, Spach.") 



A large deciduous tree, ultimately So to 100 ft. high, usually much less in 

 this country, and branching low down, forming a wide-spreading head ; 



