Citrus aurantium

The orange tree, reaching 25 ft (7.5 m) or, with great age, up to 50 ft (15 m), has a rounded crown of slender branches. The twigs are twisted and angled when young and may bear slender, semi-flexible, bluntish spines in the leaf axils. There may be faint or conspicuous wings on the petioles of the aromatic, evergreen, alternate, elliptic to ovate, sometimes faintly toothed "leaves"–technically solitary leaflets of compound leaves. These are 2 1/2 to 6 in (6.5-15 cm) long, 1 to 3 3/4 in (2.5-9.5 cm) wide. Borne singly or in clusters of 2 to 6, the sweetly fragrant white flowers, about 2 in (5 cm) wide, have a saucer-shaped, 5-pointed calyx and 5 oblong, white petals, and 20 to 25 stamens with conspicuous yellow anthers. The fruit is globose, subglobose, oblate or somewhat oval, 2 1/2 to 3 3/4 in (6.5-9.5 cm) wide. Dotted with minute glands containing an essential oil, the outer rind (epicarp) is orange or yellow when ripe, the inner rind (mesocarp) is white, spongy and non-aromatic. The pulp (endocarp), yellow, orange or more or less red, consists of tightly packed membranous juice sacs enclosed in 10 to 14 wedge-shaped compartments which are readily separated as individual segments. In each segment there may be 2 to 4 irregular seeds, white externally and internally, though some types of oranges are seedless. The sweet orange differs physically from the sour orange in having a solid center. Soil type should also be considered. The finer-textured but poorly drained soils typically found along the coastal areas and flatwoods generally will hold greater amounts of water than the coarser, deeper sands found on the Ridge areas of central Florida. The tree's rooting depth will also influence irrigation requirements. Citrus grown on well-drained sands will normally have a rooting depth of 4 to 6 feet, depending on the rootstock, with 80% of the roots in the top 3 feet of soil. Citrus grown on flatwoods soils seldom have more than 1.5 to 2 feet of rooting depth, with 98% of the roots in the top two feet of soil.