i860 The Trees of Great Britain and Ireland 



ULMUS RACEMOSA, Rock Elm 



Ulmus racemosa, Thomas, in Amer. Journ. Sci. xix. 170 (183 1) (not Borkhausen ') ; Sargent, Silva N. 



Amer. vii. 47, t 312 (1895), and in Bot. Gaz. xliv. 225 (1907). 

 Ulmus Thomasi, Sargent, Silva N. Amer. xiv. 102 (1902), and Trees N. Amer. 290 (1905). 



A tree, attaining in America 100 ft. in height and 10 ft. in girth. Bark deeply 

 divided by wide irregular interrupted fissures into broad flat scaly ridges. Young 

 branchlets densely clothed with soft white pubescence, more or less persistent in the 

 second year, when the branches are smooth, brown, and not finely striated ; usually 

 in the third year furnished with three or four irregular corky wings. Buds conic, 

 sharp-pointed, with chestnut-brown scales, covered with appressed hairs and ciliate 

 in margin. Leaves (Plate 411, Fig. 10) elliptic or oval, averaging 3 in. long and 

 if in. broad, unequal and usually subcordate at the base, shortly acuminate at the 

 apex ; upper surface glabrous, smooth, shining ; lower surface with a scattered minute 

 white pubescence throughout, conspicuous on the sides of the midrib and on the 

 nerves, not forming axil-tufts ; lateral nerves fourteen to eighteen pairs, running 

 parallel and straight to the margin, occasionally forked ; margin biserrate, non-ciliate ; 

 petiole \ in. long, glabrescent. 



Flowers in a racemose inflorescence, about i| in. long, composed of two or three 

 cymes, each with about three flowers ; axis pubescent ; pedicels slender, up to f in. 

 long, pubescent ; calyx funnel-shaped, with six to eight rounded red lobes ; stamens 

 six to eight, with slender filaments and red anthers ; stigmas pale green. Samara 

 obovate or oval, ^ to f in. long, with a slight notch at the apex, pubescent on both 

 surfaces, and densely ciliate with long white hairs on the slightly thickened margin. 



The rock elm is distributed in Canada from the province of Quebec westward 

 through Ontario, where it mainly grows on limestone, and extends southwards in the 

 United States through northern New Hampshire to southern Vermont and northern 

 New Jersey, and westward through northern New York, southern Michigan, and 

 central Wisconsin to north-eastern Nebraska and western Missouri. It is rare in 

 the east and towards the extreme western and southern limits of its range ; and is 

 most abundant and of its largest size in Ontario and the southern peninsula of 

 Michigan. It grows mainly on dry gravelly uplands, on low heavy clay soils, and on 

 rocky slopes and cliffs, in company with the sugar maple, butternut, lime, white ash, 

 beech, and other trees, but is less abundant everywhere than U. americana. 



U. racemosa is one of the rarest of American trees in this country, the only 

 specimens which we have seen being a tree at Kew, about 25 ft. high and doing very 

 badly, which was obtained from Sargent in 1875 ; a smaller tree in the Edinburgh 

 Botanic Garden, which is not thriving ; and another about 20 ft. high, growing 

 slowly at Tortworth. The tree at Kew has never produced flowers or fruit, and 

 scarcely ever develops foliage of a normal size or appearance, as it is hurt by both 

 late and early frosts. Judging from these specimens, this species, like certain 



l U. racemosa, Borkhausen, Forstbot. i. 851 (1800), is U. pedunculata, Fougeroux. 



