Sponge gourd

Sponge gourd (Luffa aegyptiaca) is an annual herbaceous vine of the cucumber family (Cucurbitaceae) with ribbed stems climbing by branched tendrils up to several metres. Leaves are alternate with roundish heart-shaped blades, shallowly 5–7 lobed and slightly hairy beneath. Flowers are unisexual and monoecious: bright yellow male flowers form long racemes, while female flowers are solitary with an elongated cylindrical ovary below the perianth; pollination is by bees, butterflies and beetles. The fruit is a long pepo, green and smooth-skinned when young, 15–30 cm long; as it matures and dries, the flesh breaks down to reveal a dense fibrous network — the classic 'loofah sponge'. Seeds are flat and black, embedded in the fibre.

The species is native to the tropical Old World (Asia and Africa) and has long been cultivated in India, China and Southeast Asia; in Vietnam it is grown throughout rural areas, typically trained on garden trellises and fruiting abundantly in summer and the rainy season. Young fruit is picked for boiling, stir-frying and soups (mướp soup with shrimp or minced pork is a cooling summer staple). Fully mature fruit is dried for its fibre — used as bath sponges, dish scrubbers and shoe insoles. In traditional medicine the fruit is sweet and neutral, clearing heat and promoting urination; the fibre and stems are used for coughs and joint pain; seeds are a folk remedy for cough and breast swelling.