Luffa operculata

Luffa operculata (common name, sponge cucumber, wild loofa or mướp xơ in Vietnamese) is a species of Luffa. It is cultivated for its fruit, which when fully ripe is strongly fibrous and is used as a fibrous scrubbing sponge for household cleaning. The fruit is a capsule with spikes. The fruit is dark-brown when mature. It is also grown in gardens and yards as an ornamental plant. In colder places they can be grown indoors as a houseplant.

The species name is derived from the word, operculum, meaning "little lid." When the fruits are mature, and the seeds are ready to be dispersed, a small part of the bottom tip (blossom end) opens up. Then, the seeds fall to the ground.