The Trees of Vermont 143 



ROSACEAE 



American Mountain Ash 



Pyrus americana (Marsh.) DC. [Sorbus americana Marsh.] 



Habit. — A small tree 20-30 feet high, with a trunk diameter of 

 12-15 inches; branches slender, spreading, forming a narrow, rounded 

 crown. 



Leaves. — Alternate, compound, 6-9 inches long. Leaflets 9-17, 

 2-3 inches long and ^-% inch broad ; sessile or nearly so, except the 

 terminal ; lanceolate to oblong-lanceolate, taper-pointed ; finely and 

 sharply serrate above the entire base ; membranaceous ; glabrous, dark 

 yellow-green above, paler beneath, turning clear yellow in autumn. 

 Petioles slender, grooved, enlarged at the base. 



Flowers. — May-June, after the leaves; perfect; ys inch across; 

 borne on short, stout pedicels in many-flowered, flat cymes 3-5 inches 

 across ; calyx urn-shaped, 5-lobed, puberulous ; petals 5, white ; stamens 

 numerous ; styles 2-3. 



Fruit. — October, but persistent on the tree throughout the 

 winter ; a berry-like pome, subglobose, % inch in diameter, bright red, 

 with thin, acid flesh ; eaten by birds in the absence of other food. 



Winter-buds. — Terminal bud about 5^ inch long, ovoid, acute, 

 with curved apex ; lateral buds smaller, appressed ; scales rounded on 

 the back, purplish red, more or less pilose above, gummy. 



Bark. — Twigs at first red-brown and hairy, becoming glabrous, 

 dark brown ; thin, light gray-brown on the trunk, smooth, or slightly 

 roughened on old trees ; inner bark fragrant. 



Wood. — Light, soft, close-grained, weak, pale brown, with thick, 

 lighter colored sapwood. 



Distribution. — Frequent throughout Vermont, becoming common 

 in the mountainous sections. 



Habitat. — Rich, moist soil on river-banks and on the borders of 

 cold swamps ; rocky hillsides and mountains. 



Notes. — This is one of the most beautiful trees of our northern 

 forests. It is conspicuous among our trees for broad, flat-topped 

 clusters of creamy white flowers followed by the persistent scarlet 

 fruits. The common name is suggested by the general resemblance 

 of the compound leaf to that of the ashes. In reality these trees are 

 very closely related to the cultivated apples and pears, a fact which will 

 become evident if one examines the structure of either the flower or 

 the apple-like fruit. The European mountain ash, Pyrus aucuparia 

 (L.) Ehrh. is planted commonly in Vermont for ornamental purposes 

 and plants of this species are abundantly spontaneous in several 

 localities. 



