ROSACEA. 
SILVA OF NORTH AMERICA. 67 
PYRUS. 
FLowenrs perfect or rarely polygamo-diecious by abortion, regular; calyx 5-lobed, 
the lobes imbricated in estivation ; petals 5, imbricated in estivation ; stamens usually 
20, or indefinite ; ovary 2 to 5-celled ; ovules 2 in each cell, ascending. Fruit a pome. 
Leaves alternate, simple or pinnate, deciduous. 
Pyrus, Linneus, Gen. 145 (excl. Cydonia). — Adanson, 
Fam. Pl. ii. 296 (excl. Cydonia). —A. L. de Jussieu, Gen. 
335.— Meisner, Gen. 106. — Endlicher, Gen. 1237. — 
Bentham & Hooker, Gen. i. 626 (excl. Cydonia and Mes- 
pilus). — Baillon, Hist. Pl. i. 403. 
Sorbus, Linnzus, Gen. 144. — Adanson, Fam. Pl. ii. 296. — 
A. L. de Jussieu, Gen. 335. 
Malus, Ruppius, FU. Jen. ed. 3, 141. — Medicus, Phil. Bot. 
i. 138. 
Torminalis, Medicus, Phil. Bot. i. 134. 
Lazarolus, Medicus, Phil. Bot. i. 135. 
Aucuparia, Medicus, Phil. Bot. i. 138. 
Chamezmespilus, Medicus, Phil. Bot. i. 188. 
Pirophorum, Necker, Hlem. Bot. ii. 72. 
Apirophorum, Necker, Hlem. Bot. ii. 72. 
Hahnia, Medicus, Gesch. Bot. 81. 
Azarolus, Borkhausen, Handb. Forstbot. ii. 1224. 
Aronia, Persoon, Syn. ii. 39 (excl. Amelanchier). 
Aria, Host, Fl. Austr. ii. 7. 
Cormus, Spach, Hist. Vég. ii. 96. 
Torminaria, Roemer, Fam. Nat. Syn. iii. 101. 
Micromeles, Decaisne, Nouv. Arch. Mus. x. 168. 
Chloromeles, Decaisne, FU. des Serres, xxiii. 156. 
Trees or shrubs, with smooth or scaly bark, terete branches, imbricated bud-scales, and fibrous roots. 
Leaves involute or conduplicate in vernation, simple, palmately lobed or unequally pinnate, usually 
serrate, deciduous ; stipules entire or lobed, free from the petiole, deciduous. Flowers in simple or 
compound terminal cymes, rarely corymbose or racemose or one or two-flowered, from buds formed the 
previous year. Bracts and bractlets subulate or foliaceous, deciduous. Calyx-tube urceolate or rarely 
turbinate, adnate to the ovary and fleshy at maturity, the five-lobed limb with acuminate reflexed lobes 
persistent, or deciduous with the apex of the receptacle. Disk lining the tube of the calyx, more or less 
thickened over the ovary. Petals white, pink, or red, suborbicular, unguiculate, inserted on the slightly 
thickened border of the disk. Stamens usually twenty, inserted in three rows, those of the outer row 
of ten parapetalous, those of the other rows alternate with them and with each other; filaments subu- 
late, free or slightly connate at the base; anthers oblong, pale, red, or purple, attached on the back, two- 
celled, the cells opening longitudinally. Carpels five, alternate with the petals, or two to four, inserted 
in the bottom of the calyx-tube and united into an inferior ovary; styles-terminal, free, or united 
below; stigmas capitate, truncate; ovules two in each cell, ascending, collateral, anatropous, the raphe 
dorsal, the micropyle inferior. Fruit an ovoid globose or pyriform pome formed by the thickening of 
the walls of the calyx-tube and its consolidation with the ovary; mesocarp more or less fleshy, the flesh 
homogeneous or granular, adherent to the one to five-celled endocarp, the cells crustaceous or cartilagi- 
nous, usually two-valved. Seeds two or by abortion one in each cell, ovate, acute, erect, exalbuminous ; 
testa usually cartilaginous, chestnut-brown and lustrous, slightly mucilaginous on the outer surface. 
Embryo erect; cotyledons plano-convex, fleshy ; radicle short, inferior. 
1 The genus Pyrus may be divided into the following sections 
which some authors consider entitled to the rank of genera : — 
Mavs. 
lateral branchlets ; ovary 3 to 5-celled ; styles more or less united 
below. Fruit globose, umbilicate or rounded at the base ; the flesh 
Flowers fascicled or subumbellate on short spur-like 
homogeneous. Leaves entire, or laciniate on vigorous shoots. 
Pyrus. Flowers in few-flowered corymbs on short spur-like 
lateral branchlets ; ovary 5-celled ; styles free. Fruit pyriform 
or subglobose, tapering at the base, the flesh granular. Leaves 
simple. 
Arr. Flowers in corymbose cymes ; ovary 2 to 5-celled styles 
free, Fruit pyriform or globose; flesh granular. Leaves entire 
or lobed. 
Aronia. Flowers in compound corymbs ; ovary 4 or 5-celled ; 
styles united at the base. Fruit berry-like, pyriform or subglobose. 
Leaves simple, their midribs glandular on the upper side. 
