Holostylon

Herbs or subshrubs with 1 or more erect, virgate stems arising from a perennial base. Leaves often quite large, margin toothed. Inflorescences terminal, paniculate, often occupying a third or more of the plant; bracts minute, each subtending a single flower. Calyx not or slightly gibbous at base, subequally 5-toothed, accrescent; tube campanulate; teeth short, deltoid to deltoid-lanceolate. Corolla bilabiate; tube short, declinate, bent and expanding just beyond calyx; upper lip erect, short, obscurely 4-lobed; lower lip large, boat-shaped. Stamens 4, declinate, arising from mouth of corolla tube and lying in lower lip; filaments united at base into a sheath open above. Style slightly exceeding stamens; stigma entire. Nutlets subrotund, slightly compressed, triquetrous, glabrous.