235 species (205 belong to Oxalis); chiefly in S. Africa and Trop. America.—Oxalate of potash is contained in the leaves of Oxalis.
Order 2. Linaceæ. Herbs with scattered or opposite, sessile, simple, small, entire leaves, without (rarely with small) stipules. The flowers (Fig. [430]) are regular, 5- or 4-merous. Petals are free, twisted, quickly falling off. Stamens united at the base; the petal-stamens are either reduced to teeth (Fig. [431] A, m) or entirely suppressed. Styles free. The (5–4) epipetalous loculi of the ovary are incompletely halved by false divisional walls, each half contains one ovule (Fig. [431] C). The fruit is a spherical capsule, dehiscing along the divisional wall (Fig. [432]); the 10 (-8) seeds have a straight embryo and very slight endosperm (Fig. [433]).
Figs. 430–433.—Linum usitatissimum.
Fig. 430.—The Flax plant.
Fig. 431.—A Flower after removal of sepals and petals; m petal-stamens reduced to teeth. B Longitudinal section of ovary. C Transverse section of capsule.
Fig. 432.—Capsule (nat. size).
