ROSACEA. SILVA OF NORTH AMERICA. 81 
PYRUS SAMBUCIFOLIA. 
Mountain Ash. 
LEAFLETS oblong-ovate to lance-ovate, mostly obtuse. 
Pyrus sambucifolia, Chamisso & Schlechtendal, Linnea, Pyrus Americana, Newberry, Pacific R. R. Rep. vi. 73 
ii. 86. — Don, Gen. Syst. ii. 648. — Torrey & Gray, FU. (not De Candolle). — Cooper, Pacific R. R. Rep. xii. pt. ii. 
NV. Am. i. 472. — Walpers, Rep. ii. 53.— Dietrich, Syn. 60. — Torrey, Bot. Wilkes Explor. Exped. 292. 
iii. 155. — Watson, King’s Rep. v. 92.— Brewer & Wat- Pyrus aucuparia, Meyer, Pl. Lab. 81 (in part). — Schlecht- 
son, Bot. Cal. i. 189.— Sargent, Forest Trees N. Am. endal, Linnea, x. 99 (in part). — Hooker, Trans. Linn. 
10th Census U. 8. ix. 74. — Watson & Coulter, Gray’s Soc. xxiii. 290, 327 (in part). 
Man. ed. 6, 164. Sorbus sambucifolia, Roemer, Fam. Nat. Syn. iii. 139. — 
Sorbus aucuparia, var. 8., Michaux, 77. Bor-Am. i. 290. Wenzig, Linnea, xxxviii. 73. — Decaisne, Nouv. Arch. 
Sorbus aucuparia, Schrank, Pf. Lab. 25 (in part; not Lin- Mus. x. 159. 
nus). Sorbus Sitchensis, Roemer, Fam. Nat. Syn. iii. 189. 
A tree, occasionally thirty fect in height, with a trunk sometimes a foot in diameter, and spreading 
branches which form a round handsome head; or often on the mountains of western America a low 
shrub. The bark of the trunk is a quarter of an inch thick, with a smooth gray satiny surface some- 
times broken by small appressed scales. The branchlets are at first glabrous, pubescent, or pilose with 
long pale hairs, and in their first winter are brown tinged with red and are marked by scattered 
oblong lenticular spots. The winter-buds are acute, often three quarters of an inch to an inch in 
length, and in the shape, color, and texture of the scales which cover them hardly distinguishable from 
those of Pyrus Americana. The leaves are four to six inches long, with stout grooved and usually 
bright red petioles often tufted with dark hairs at the base of the petiolules, and seven to thirteen 
oblong-oval or lance-ovate leaflets ; these are generally blunt and rounded, or abruptly short-pointed, or 
acuminate at the apex, unequally wedge-shaped at the base, entire or undulate below, and sharply and 
often doubly serrate above the middle, with spreading and sometimes glandular teeth ; when they unfold 
they are pubescent on the lower surface, and at maturity are glabrous, dark green above, and pale 
below, with inconspicuous midribs and veins, and are sessile or short-petiolulate, or the terminal one 
long-stalked, and an inch and a half to two inches in length and one half to three quarters of an inch 
in breadth. The stipules are lanceolate to triangular, foliaceous, from one half to three quarters of an 
inch long, and early deciduous. The leaves turn a deep orange-color in the autumn before falling. The 
flowers, which appear in the early part of July, are produced in small dense pubescent cymes two to 
three inches across ; they are a quarter of an inch in diameter when fully expanded, and are borne on 
slender clavate pedicels twice the length of the obconic calyx; this is glabrous or puberulous on 
the outer surface with narrow acute rigidly pointed lobes ciliate on the margins and much shorter 
than the obovate petals which are rounded above and contracted below into short claws. The fruit is 
subglobose, bright scarlet, and sometimes nearly half an inch in diameter, and is produced in dense 
red-branched clusters. 
Pyrus sambucifolia is distributed from southern Greenland! to Labrador? and the high moun- 
tains of northern New England, and ranges westward along the northern shores of the Great Lakes to 
those of Little Slave Lake, through the Rocky Mountains to Alaska*® and Kamschatka,! and through 
1 Hooker f. Trans. Linn. Soc. xxiii. 290, 327 (Distribution Arctic Rothrock, Smithsonian Rep. 1867, 446 (Fl. Alaska). — Macoun, Cat. 
2p hy), Can. Pl. i. 146. 
2 Meyer, Pl. Lab. 81. 4 Ledebour, Fl. Ross. ii. 99. 
8 Bongard, Mém. Acad. Sci. St. Pétersbourg, ser. 6, ii. 183.— 
