Popo Sewing Kit is another name for Metaplexis japonica, so called because its fruit resembles a sewing kit.

Popo Sewing Kit is the folk name for Metaplexis japonica (rough potato). It is a perennial herbaceous twining vine in the dogbane family (Apocynaceae), formerly often placed in the milkweed family (Asclepiadaceae). The name is vividly apt: its fruit is a small spindle-shaped pod, and when ripe the pod splits open to reveal seeds topped with white silky hairs, looking just like the needles and thread spilling out of a sewing kit, which is how it got its rural name. In some places, closely related plants with similar fruit shapes are casually called by the same name, a common case of folk names being used interchangeably.

The stems of Metaplexis japonica are slender and twining, and exude white milky sap when broken; the leaves are opposite and ovate-cordate. In summer it bears small white-green flowers, often with pale purple markings, gathered into umbel-like inflorescences, and in autumn it produces paired follicles. It is distributed across most of China, commonly found at field edges, roadsides, forest margins and old fences, with very strong adaptability.

In folk practice, the fruit husks of Metaplexis japonica are often collected as a medicinal material called Tianjiangqiao, traditionally used mainly for relieving cough and reducing phlegm, and the roots and whole plant also have medicinal records. These are folk experiences; consult a professional before use, and it is not advisable to gather and consume it as medicine on your own. In addition, its flowers produce nectar during the flowering period and can attract bees and butterflies, making it a common nectar-source plant in the countryside; the tender stems and leaves are also eaten as a spring wild vegetable in some areas, but they taste numbing and astringent if not processed properly, so those unfamiliar with them are advised not to try it casually.

When growing it at home, Popo Sewing Kit likes a sunny, well-drained environment, tolerates drought and poor soil, and is easy to establish from seed or by dividing the rhizomes, requiring relatively rough-and-ready care. Its underground rhizomes spread vigorously, and its seeds drift on the wind with their white hairs, so when planted in the ground, watch out and control its spread, promptly pulling up surplus suckers and clearing away ripe seed pods. The white sap is irritating to skin and eyes, so it is best to wear gloves when pruning or harvesting, and wash your hands promptly afterwards.