Stephania japonica aka Tapevine

Stephania japonica is a vine in the Menispermaceae family. Its native range spans Asia's tropical and subtropical zones. It reaches as far as the southern Pacific. Records list southern China, Japan, Korea, and the Indian subcontinent. It also grows in Southeast Asia, New Guinea, and Australia. Kew places it in the wet tropical biome. It is not native to Britain or Ireland.

The plant has a woody rootstock and thin stems. The stems can grow somewhat woody with age. Climbing is the main growth trait the sources describe. They give no sound size range for full-grown plants. This applies to both height and spread. They give no leaf size or detailed leaf shape. The account describes the root as tuberous and bitter. It shows flowers, fruit, and stems with leaves. No text describes the flower colour or fruit shape.

In southern China, it grows near villages and woodland edges. It grows in scrub, open woods, and limestone hills too. Elsewhere, records place it in woods that have grown back. They also list other sites with new growth. It grows in hedges, thickets, and on riverbanks. It also grows in swamps with Nypa palms. Records reach heights of about 6,560 feet [2,000 metres]. These are wild sites, not tested garden settings. The sources give no firm light, water, or soil needs. They give no cold-hardiness rating or time of bloom.

People pick wild leaves for food and use as medicine. They press juice from the leaves to make jelly. This records a prepared food, not leaves safe for unrestricted use. In folk medicine, people use roots for several gut and urinary problems. Other uses include fever, hepatitis, and itching. People crush the leaves and mix them with water. This forms a gel, which they apply to breast infections. These are records of past practice, not proof that treatments work.

The species account warns that the root is highly poisonous. It links this risk to a compound called picrotoxin. The plant also has many alkaloids, compounds with reported biological effects. Its past use as medicine does not make home treatment safe. In Thailand, leaf extracts had weak effects that killed fruit flies. The sources list seeds as a way to grow new plants. They report no garden pests or diseases. They give no tested landscape uses or methods for growing it.