A member of Curcubitaceae, calaica is the fruit of a vine. Our colleague Dr. Larry David Wilson tell us: “[Calaica] is a slender vine with lobed, palmate leaves. It is dioecious, so each plant has both male and female flowers. Its area of origin is not known, but it is widespread in the tropics around the world. It has both culinary and medicinal uses. [My wife] Betty tells me that some folks in Honduras make a tea of it to be drunk by sufferers of diabetes.”
Wikipedia says it is native to India and was transported to China in the 14th Century. The rest, we presume, is history.