356 TREES OF NORTH AMERICA 



A tree, 30-40 high, with a trunk 12'-18' in diameter, and slender branchlets 

 coated at first with long pale hairs soon deciduous or persistent until the autumn, 

 becoming bright red and lustrous, and later dark brown and marked by minute 

 remote pale leuticels; often a shrub with numerous slender stems. Winter-buds 

 obtuse, T y long, chestnut-brown, the inner scales at maturity lanceolate, usually 

 bright red and nearly ^' in length. Bark \' thick, and covered by large thin loose 

 light red-brown plate-like scales. Wood heavy, hard, very close, light brown tinged 

 with red, with lighter colored sap wood of 2030 layers of annual growth; used 

 for mallets, mauls, the handles of tools, and the bearings of machinery. The fruit 

 has a pleasant subacid flavor. 



Distribution. Deep rich soil in the neighborhood of streams, often forming 

 almost impenetrable thickets of considerable extent; Aleutian Islands southward 

 along the coast and islands of Alaska and British Columbia to Sonoma and Plumas 

 counties, California; of its largest size in the valleys of Washington and Oregon. 



Occasionally cultivated as an ornamental plant in the eastern states, and in western 

 Europe. 



4. SORBUS, L. Mountain Ash. 



Trees or shrubs, with smooth aromatic bark, stout terete branchlets, large buds 

 covered by imbricated scales, the inner accrescent and marking the base of the 

 branchlet by conspicuous ring-like scars, and fibrous roots. Leaves alternate, pinnate 

 in the American species, the pinnae conduplicate in the bud, serrate, deciduous; 

 stipules free from the petioles, foliaceous. Flowers in broad and terminal leafy 

 cymes; calyx-tube urn-shaped, 5-lobed, the lobes imbricated in the bud, persist- 

 ent; petals rounded, abruptly narrowed below, white; stamens usually 20 in 3 

 series, those of the outer series opposite the petals; carpels 2-5, usually 3; styles 

 usually 3, distinct; ovules 2 in each cell, ascending; raphe dprsal; micropyle infe- 

 rior. Fruit a small subglobose red or orange-red pome with acid flesh, and papery 

 carpels free at the apex. Seeds 2, or by abortion 1, in each cell, ovate, acute, erect; 

 seed-coat cartilaginous, chestnut-brown, and lustrous; embryo erect; cotyledons 

 plano-convex, flat; radicle short, inferior. 



Sorbus is widely distributed through the northern and elevated regions of the 

 northern hemisphere with three or four species in North America of which one is 

 arborescent. Of exotic species, Sorbus Aucuparia, L., the European Mountain Ash, 

 is often cultivated as an ornamental tree in Canada and the northern states and has 

 become sparingly naturalized northward. 



Sorbus is the classical name of the Pear or of the Service-tree. 



1. Sorbus Americana, Marsh. Mountain Ash. 



Leaves 6'-8' long, with slender grooved dark green or red petioles, often with 

 tufts of dark hairs at the base of the petiolules, and 13-17 lanceolate acute taper- 

 pointed leaflets unequally wedge-shaped or rounded and entire at the base, sharply 

 serrate above, with acute often glandular teeth, sessile or short-stalked, or the 

 terminal leaflet on a stalk sometimes % long; when they unfold slightly pubescent 

 below, at maturity membranaceous, glabrous, dark yellow-green on the upper and 

 pale on the under surface, 2'-3' long, '-f wide, with prominent midribs and thin 

 veins, turning bright clear yellow before falling in the autumn; stipules broad, nearly 

 triangular, variously toothed, caducous. Flowers appearing after the leaves are 

 fully grown, ^' in diameter, on short stout pedicels, in flat cymes 3'-4/ across, with 



