The sponge gourd is a herbaceous annual plant related to the cucumber. The flowers are large and yellow and bell-shaped. The fruits themselves have a network of vessels inside which, when the fruit ripens, becomes dry. The picked fruits are then stripped of their peel and soaked in water for a few days so that the flesh and seeds can be removed. The “fruit” that remains is then dried further and used as a sponge (the luffa sponge). The small fruits are sometimes eaten as pickles.