Exotic trees from the East and West Indies, little known in Britain. Heistria coccinea, a native of Martinique, is said to be the Partridge wood of the cabinet-makers.
ORDER XXXVII.—AURANTIACEÆ.—THE ORANGE TRIBE.
Fig. 121.—Flower and seed of the Orange.
The natural order Aurantiaceæ contains fourteen genera; but the only one I think my readers will feel an interest in is the genus Citrus. This genus comprises, among several other species, C. medica, the Citron; C. Limetta, the sweet Lime; C. Limonum, the Lemon; C. Paradisi, the Forbidden fruit; C. decumana, the Shaddock; C. Aurantium, the Sweet Orange; and C. vulgaris, the Bitter or Seville Orange. to these may be added C. nobilis the Mandarin Orange, the fruit of which is reddish, and which parts naturally from its rind, which is sweet, and may be eaten. All the species agree in having a tube-like calyx, scalloped into five short teeth, and a flower of generally five fleshy petals, (see a in fig. [121]), though the number occasionally varies from four to nine. These petals are elliptic in shape, concave, and always widely opened. In the centre of the flower are the stamens, varying from twenty (which is the ordinary number) to sixty; the anthers are two-lobed, and oblong, and the filaments are somewhat thickened at the base, and united there into several small bundles (b), but free above. The pistil has a somewhat globular ovary, with a cylindrical style, termi nating in a stigma, which is slightly raised in the centre. The disk in which the stamens are inserted, forms a ring round the ovary. The fruit (fig. [122]), which is considered by botanists to be a kind of berry, is in fact a seed-vessel with numerous cells, divided by dissepiments and a central placenta (a); the cells being the quarters of the Orange, the dissepiments the divisions between them, and the placenta the central pith. When the flower first expands, the ovary, if cut open and examined, will be found to be divided into several cells, each containing two rows of ovules. As in the preceding genera, however, many of these ovules become abortive; and as the cells fill gradually with cellular pulp, the seeds become detached from the placenta, and buried in it. The seeds themselves are very interesting; they are covered with a thick wrinkled skin, and they show distinctly the hilum (c in fig. [121]), the chalaza (d) and the raphe or connecting cord between them, parts which are seldom to be distinguished in seeds with the naked eye.
Fig. 122.—Leaf and fruit of the Orange.