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DescriptionCreeping perennial herbs, rooting at the nodes. Leaves opposite, simple, subentire to toothed; lamina with appressed, medifixed hairs. Inflorescences ± long-pedunculate, axillary, short, ovoid to cylindric, very dense bracteate spikes. Calyx membranous, 2-lobed, flattened. Corolla with short tube and spreading irregularly ± 4-lobed limb. Stamens 4. Fruit of 2 nutlets, enclosed by a persistent calyx.