51�Թ�

Chiefly herbs, with square stems, opposite aromatic leaves, more or less 2-lipped corolla, didynamous or diandrous stamens, and a deeply 4-lobed ovary, which forms in fruit 4 little seed-like nutlets or achenes, surrounding the base of the single style in the bottom of the persistent calyx, each filled with a single erect seed.—Nutlets smooth or barely roughish and fixed by their base, except in the first tribe.

Corolla tubular, obviously 2-lipped; the upper lip narrow, erect or arched, enclosing the 4 usually strongly didynamous stamens.

Woody plants, monopetalous, didynamous or diandrous, with the ovary commonly 2-celled by the meeting of the two parietal placentæ or of a projection from them, many-ovuled; fruit a dry capsule, the large flat winged seeds with a flat embryo and no albumen, the broad and leaf-like cotyledons notched at both ends.—Calyx 2-lipped, 5-cleft, or entire.

Fertile stamens 4 and didynamous, or 2.

Stamens 2 or 4, not approaching in pairs nor strongly didynamous; anthers 2-celled.