is a perennial herb inhabiting forests in mountainous regions. Stems
measure15-30cm in height, and the lower parts sparsely branch, with
hairs on one side. Leaves are of opposite phyllotaxis, in an oval
shape. T. japonicum is dioecious; it has membranaceous stipules at
the bases of petioles and sets 1 or 2 novel shapes of male or
U-shaped female flowers. The male flowers hang many stamens, and
three sepals bend backward around. Bloom time: April-May.