POMACEAE. 515 



or less fleshy pome, consisting of the thickened calyx-tube enclosing the 

 bony papery or leathery carpels. Endosperm none ; cotyledons fleshy. 

 About 20 genera and 225 species, of wide geographic distribution. 



Ripe carpels papery or leathery. 



Leaves pinnate. I. Sorbus. 



Leaves simple, entire, toothed, or lobed. 



Cavities of the ovary (carpels) as many as the styles. 



Flesh of the pome with grit-cells. 3. Pyrus. 



Flesh of the pome without grit-cells. 



Cymes simple ; trees. 3. Malus. 



Cymes compound ; shrubs. 4. Aronia. 



Cavities of the ovary becoming twice as many as the styles. 5. Amelanchier. 

 Ripe carpels bony. 



Ovule i in each carpel, or if 2, dissimilar. 6. Crataegus. 



Ovules 2 in each carpel, alike. 7. Cotoneaster 



i. SORBUS L. 



Trees or shrubs, with pinnate leaves, serrate leaflets, deciduous stipules, and 

 white flowers, in compound cymes. Calyx-tube urn-shaped, 5-lobed, not bracteo- 

 late. Petals 5, spreading, short-clawed. Stamens co . Ovary inferior ; styles 

 usually 3, distinct; stigma truncate; ovules 2 in each cavity. Fruit a small red 

 berry- like pome. [The ancient Latin name of the Pear or Service-tree.] About 7 

 species, natives of the north temperate zone. Besides the following, another occurs 

 in western N. Am. 



Leaflets glabrous above. 



Leaflets long-acuminate; fruit 4-6 mm. in diameter. i. S. Americana. 



Leaflets obtuse or short-pointed; fruit about 8 mm. in diameter. 



2. S. sambucifolia. 

 Leaflets pubescent on both sides. 3. S. Aucuparia. 



i. Sorbus Americana Marsh. AMERICAN MOUNTAIN ASH. DOGBERRY. 

 (I. F. f. 1975.) A small tree, with smooth bark. Leaves petioled; leaflets 11-17, 

 lanceolate, long-acuminate, glabrous, or slightly pubescent, bright green above, gen- 

 erally paler beneath, 3-10 cm. long; cymes dense, 7-15 cm. broad; flowers 4-6 mm. 

 broad. In moist ground, Newf., Manitoba, N. Car. and Mich. May-June. 



2 Sorbus sambucifolia (C. & S.) Roem. WESTERN MOUNTAIN ASH. 

 (I. F. f. 1976.) Resembles the preceding. Leaflets 7-15, proportionately broader 

 and shorter, oval or ovate- lanceolate, obtuse or short-pointed at the apex, glabrous 

 and dark green above, pale and usually more or less pubescent beneath, especially 

 along the veins, seldom over 7 cm. long; flowers 6-7 mm. broad; calyx and pedi- 

 cels generally pubescent; cymes 5-10 cm. broad. In moist ground, Lab. to 

 Alaska, northern N. Eng., Penn., Mich., and in the Rocky Mts. to Colo, and 

 Utah. Also in northeastern Asia. June -July. 



3. Sorbus Aucuparia L. EUROPEAN MOUNTAIN ASH. Leaves pubescent 

 on both sides, especially when young, the calyx and pedicels usually woolly. 

 Escaped from cultivation, N. S. to N. H. Native of Europe. 



2. PYRUS L. 



Trees, or some species shrubs, with simple leaves. Flowers large, white or 

 pink, in simple cymes. Calyx urn-shaped, 5-lobed, the lobes acute. Petals 5, 

 rounded, short-clawed. Stamens usually numerous; styles mostly 5, distinct, or 

 united only at the very base; ovules 2 in each cavity; carpels cartilaginous or 

 leathery. Fruit a pome, usually pear-shaped, its flesh abounding in grit-cells. 

 [Latin name of the Pear.] About 12 species, natives of the Old World. 



i. Pyrus comrrmnis L. PEAR. CHOKE PEAR. (I. F. f. 1977.) A tree, 

 sometimes 20 m. high; branches usually thorny. Leaves ovate, elliptic or obo- 

 vate, finely serrulate or entire, petioled, 3-8 cm. long, downy and ciliate when 

 young, becoming glabrous or nearly so, the apex acute or acuminate; petioles 

 sometimes as long as the blades or longer; cymes few-several-flowered, borne at 

 the ends of short twigs of the preceding year; pedicels 1.5-5 cm - l n R; flowers 

 white, 2-5 cm. broad ; calyx-lobes about as long as the tube; styles distinct to the 



