A gourd is a plant of the family Cucurbitaceae, particularly Cucurbita and Lagenaria or the fruit of the two genera of "calabash tree", Crescentia and Amphitecna. The term refers to a number of species and subspecies, many with hard shells, and some without. Likely one of the earliest domesticated types of plants, subspecies of the bottle gourd, Lagenaria siceraria, have been discovered in archaeological sites dating from as early as 13,000 BC. Today, research is being conducted into bitter gourds, Momordica charantia, to reduce its unpleasant taste while keeping the nutritional and medicinal benefits. Gourds have had numerous uses throughout history, including as tools, musical instruments, objects of art, film and food.