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DescriptionAnnual or perennial herbs. Leaves opposite, ovate to linear, entire, sessile. Flowers solitary or in axillary clusters, bisexual, zygomorphic. Bracts resembling leaves. Bracteoles 0. Calyx deeply 5-lobed, sometimes one lobe longer and broader than the others. Corolla 2-lipped, tube cylindric below, upper lip 2-lobed with lobes recurved, lower lip 3-lobed, lobes sometimes reflexed. Stamens 4, didynamous. Fruit a linear capsule.