ORDER LXVIII.--ROSACEÆ.--(SEE CHAP. III. IN P. 50.)
The flowers have five sepals, combined in their lower part into a tube, but divided above into five lobes; and the corolla has generally five petals. There are numerous carpels, which are usually inclosed in the fleshy tube of the calyx. The ovary is one-celled, and there is seldom more than one seed, and scarcely ever more than two. The leaves are alternate, generally compound, and always furnished with stipules. De Candolle divides the order into eight tribes, viz., 1. _Chrysobalaneæ_; 2. _Amygdalineæ_; 3. _Spiraceæ_; 4. _Neuradeæ_; 5. _Dryadæ_, or _Potentilleæ_; 6. _Sanguisorbeæ_; 7. _Roseæ_; and 8. _Pomaceæ_. Of these, the first, second, third, and eight, are made separate orders; the fifth, sixth, and seventh are retained in Rosaceæ. Neuradeæ was first removed to Ficoideaceæ, and afterwards made a separate order; and another order has been made, called Quillageæ, including only the genera Kageneckia and Quillaja.
There are only two genera in this order, both of which are remarkable for the fragrance of their flowers. The American Allspice (_Calycanthus floridus_) is a shrub, with very dark blackish purple flowers, which botanists consider to be all calyx, the plants in this order having no petals. The lobes of the calyx are somewhat leathery in texture, and lanceolate in form; they are very numerous, and they are disposed in several rows, like scales. The stamens are numerous, but only the outer twelve are fertile, and they soon fall off. The peduncle is thickened below the flower; and the receptacle is dilated, and drawn out over the carpels, which are arranged in it like those of the rose, which they closely resemble, but are much larger. The leaves are opposite and feather-nerved. _Chimonanthus fragrans_, so well-known for its beautiful yellowish flowers, which are produced about Christmas, belongs to this order. In this plant the lobes of the calyx are oval, and not nearly so numerous as in Calycanthus; the outer lobes look like bracts. The stamens are less numerous, and not deciduous; and only five are fertile, which are united at the base. This plant was formerly called _Calycanthus præcox_.
This order has only one genus and two species. The Pomegranate (_Punica Granatum_) has a tubular calyx, with a limb in five or seven divisions, and the same number of petals as there are segments to the calyx. The calyx and corolla are both of the same colour. When the petals fall, the tube of the calyx swells, and becomes a many-celled berry, the limb of the calyx remaining on, and forming a kind of crown to the fruit. The cells are divided into two parts, and they contain a great number of seeds which are plunged in a juicy pulp. The other species, _P. nana_, only differs in being a dwarf plant, and in the leaves being narrower. The Pomegranate was formerly included in Myrtaceæ.