Description from Flora of China
Herbs. Branches usually acutely 4-angled, sometimes spiny, hirsute, glandular. Leaves opposite. Inflorescences terminal, spicate or capitate, elongated in fruit; bracts obovate. Flowers small. Calyx membranous, 2-lipped, 4-lobed. Corolla sometimes 2-lipped; lobes 5, spreading. Stamens 4, didynamous, inserted on distal part of corolla tube, included. Ovary 2-locular; ovule 1 per locule. Style short; stigma capitate. Capsules small, splitting into 2 1-seeded cocci.
About ten species: Africa, America, and Asia; one species in China.
Phyla has often been combined with Lippia but differs in characters such as herbaceous habit, elongated infructescences, and obovate bracts.