Fraxinus 909. 



dense white pubescence, which is retained in the second year ; lenticels white, 

 inconspicuous. Leaflets (Plate 263, Fig, 13), seven to nine, occasionally five, 3 to 

 5 inches long, three times as long as broad, ovate-lanceolate to oblong-lanceolate, 

 tapering at the base, acuminate at the apex, finely serrate and ciliate in margin ; 

 upper surface with scattered fine pubescence; lower surface densely pubescent 

 and green in colour. The leaflets are usually distinctly stalked, with pubescent 

 petiolules; but forms occur in which they are subsessile, the substance of the 

 leaflet being prolonged to its insertion, Rachis of the leaf densely white pubescent, 

 with a distinct shallow groove on its upper side. 



Flowers (section Leptalix) dioecious, in tomentose panicles in the axils of the 

 leaf-scars of the preceding year's shoot; corolla absent. Fruit linear - spatulate, 

 surrounded at the base by the persistent calyx ; body slender, terete, many-rayed ; 

 wing slightly decurrent, narrow, and rounded or acute at the apex. 



For the distinctions between this species and the Oregon ash, see under the 

 latter, Fraxinus Biltmoreana differs conspicuously in having the leaflets white 

 beneath, Fraxinus profunda, Bush,^ which is remarkably distinct in its fruit, differs 

 also in having the leaflets entire or undulate in margin, their base being usually very 

 asymmetrical. 



There are several forms of F. pennsylvanica in cultivation, some having the 

 leaflets very firm in texture and set close on the rachis, others having thin leaflets 

 wider apart on the rachis. The leaflets also vary in the length of their stalklets, in 

 the size of the serrations, and in the shape of the base, which may be gradually 

 tapering or abruptly tapering and almost rounded. F. Richardi, F. Boscii, and 

 F. glabra, names given to certain horticultural varieties, are all probably referable to 

 this species. 



Var. aucubcefolia (F. aucubcsfolia, Kirchner, Arb. Muse. 507 (1864)), in which 

 the leaves are variegated with yellow, is considered by Lingelsheim ^ to be a hybrid 

 between F. pennsylvanica and F. lanceolata. At Aldenham ' this forms a handsome 

 tree about 30 feet high, (A. H.) 



It is neither so large nor so common a tree as the white ash in the United States 

 where, according to Sargent, it has nearly the same distribution as the latter ; being 

 most common and largest in the north Atlantic States, smaller and less abundant 

 west of the AUeghanies. Macoun says * that in Canada it ranges farther west than 

 the white and black ashes, growing along the Assiniboine river and the tributaries of 

 Lake Manitoba, It is usually 40 to 60 feet high, with a diameter rarely exceeding 

 18 inches to 20 inches ; and is here of no value for timber, but makes good firewood, 

 even when green. Emerson measured a tree at Springfield in September 1840 

 which was 9 feet in girth at 3 feet from the ground; and Ridgway says^ that 

 Dr, Schneck measured a tree in the Wabash forests 138 feet high by 16 feet in 

 girth. 



» See Sargent, Trees N. America, 772. This ash, which is probably not yet introduced, grows to a great size in 

 river swamps in Missouri, Arkansas, and Florida. It is considered by Lingelsheim, in Engler, Bot. Jahrb. xl. 220 (1907), to 

 be a variety of ^. pennsylvanica. ^ Op. cit. 222. 



' It is cultivated here under the erroneous name, F. americana, var. aucubafolia, which is given in Kew Handlist of Trees, 

 S33 (1902). 4 Forest Wealth of Canada, p. 23. « Proc. U.S. Nat. Mus. xvii. 411 (i894)- 



