PYRUS
- Pyrus, Linnæus, Gen. Pl. 145 (1737); Bentham et Hooker, Gen. Pl. i. 626 (1865).
- Malus, Ruppius, Fl. Jen. ed. 3, 141 (1745); and Medicus, Phil. Bot. i. 138 (1789).
- Sorbus, Linnæus, Gen. Pl. 144 (1737).
Trees and shrubs belonging to the sub-order Pomaceæ of the order Rosaceæ. Branchlets of two kinds, long and short shoots, the flowers in certain species being borne on the latter only. Leaves deciduous, alternate, stalked, simple or pinnate; stipules deciduous. Flowers in cymes or corymbs, regular, perigynous or epigynous, calyx-lobes 5, petals 5. The receptacle (the end of the axis) is hollowed out, the ovary being attached to its interior. A disc is present, either annular or coating the receptacle. Ovary with 2 to 5 cells, each cell containing 2 ovules. Fruit, a pome, the external fleshy part being formed of the receptacle, while the interior or core is the developed ovary; cells 2 to 5, with a membranous or cartilaginous endocarp, each containing 1 or 2 seeds, though occasionally some are empty.
The genus Pyrus has been divided variously into sections, which some botanists treat as distinct genera. The following arrangement is perhaps the simplest:—
A. Leaf in the bud rolled inwards towards the midrib.
- 1. Pyrophorum. Flowers in corymbs on spur-like branchlets, ovary with 5 cells, styles free. Fruit pyriform or hollowed out at the base, flesh granular. Leaves simple. Pears: confined to Asia and Europe.
- 2. Malus. Flowers fascicled or umbellate on spurs, ovary with 3 to 5 cells, styles united at the base. Fruit with a cavity at the base, flesh homogeneous. Leaves simple. Apples: species in North America as well as in Europe and Asia.
- 3. Aronia. Flowers in terminal corymbs, ovary with 4 to 5 cells, styles free or united at the base. Fruit small, not hollowed at the base, endocarp very thin, flesh almost homogeneous. Leaves simple, crenate, with the midrib glandular on its upper side. Two North American shrubs.
B. Leaf folded in the bud. Flowers in terminal corymbs.
- 4. Hahnia. Ovary with 2 to 3 cells, styles united below. Fruit crowned by the calyx, and having a hard, almost bony endocarp, flesh granular. Leaves simple, lobed. Pyrus torminalis, the only species.
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