O. Ryding (2006) Leucas. Flora of Somalia 3: 325-330
Plants herbs or shrubs, all hairs unbranched. Inflorescences thyrselike, open or dense; bracts more or less leaflike; cymes with 1-many flowers, usually dense, often forming globose verticillasters, with bracteoles. Calyces 5-10-lobed, usually distinctly zygomorphi, distally about 10-ribbed, sometimes with a ring of hairs inside the tube; lobes usually unequal, sometimes equal; corollas 2-lipped, white to cream; upper lips hooded, emarginate, usually more or less falcate, sometimes almost straight, densely hairy and beared along the margins with white or cream hais; lower lips straight or deflexed, 3-lobed, the muddle lobe usually larger and often emarginate; stamens included in the upper coroola lipes; style branches usually unequal, the lower distinctly longer, sometimes subequal. Nutelets obovoid, obpyramidale, oblong, or ellipsoid, often sharply trigonous, truncate or rounded at the top, usually with sessile glands at the top, sometimes glandular all over.
Leucas includes about 100 species. They are native to tropical Africa and Asia. Some are established in other parts of the tropics.
Note: GBIF records include introduced and cultivated plants. Consequently, the distribution shown often differs from statements about a taxon's native distribution.
