CLASS XII. ORDER III., IV. 207 



TRIGYNIA. 



217. SORBUS. 



SoRBUS Americana. Muhl. Mountain Ash. 



Leaves pinnate, leafets glabrous, acute, siibequally 

 serrate, petioles glabrous. 

 Syn. SoRBus aucuparia, §. Mx. 



Pyrus Americana. De Cand. 

 A small tree, common in mountain woods in the northern 

 parts of New England. It is more slender and irregular in its 

 growth than the cultivated S. aucuparia of Europe. Leaves 

 pinnate, smooth ; leafets oblong-lanceolate, rounded at base, 

 sharply serrate, pale underneath. Flowers white, in terminal 

 corymbs. — I have not seen it nearer to Boston than Wachusett 

 hill, where it flowers the first of June. 



PENTAGYNIA. 



218. PYRUS. 



Pyrus arbutifolia. Willd. Choke Berry. 



Leaves obovate, acuminate, serrate, downy under- 

 neath, the midrib glandular above ; flowers in- co- 

 rymbs. 



Syn. Mespiltjs arbutifolia. Lin. Mich. 

 Aronia arbutifolia. Pe.rs. 



A slender shrub. Leaves oblong, oval, or obovate, finely ser- 

 rate, the midrib spotted on the upper side, with small, dark 

 glands. Flowers white, in compound, downy corymbs. Pedun- 

 cles and calyx more or less downy. Petals roundish, concave. 

 Filaments white, anthers crimson. Germ woolly, styles five, 

 straight ; stigmas capitate. Fruit with five cells and ten seeds, 

 of the size of large whortleberries, rough, and astringent to the 

 taste. — Low woods and thickets. — May, June. 



Pyrus ovalis. Willd. Sicamp Pyrus. 



Leaves oblong, acute, downy when young; flowers 

 racemed ; petals obovate ; calyx pubescent, 



