Melothria scabra

Melothria scabra, also known as the cucamelon, is a vine grown for its edible fruit. Fruits are about the size of grapes and taste like cucumbers with a tinge of sourness. Vernacular names include mouse melon, Mexican sour gherkin, cucamelon, Mexican miniature watermelon, Mexican sour cucumber and pepquinos.[1][2][3]
This plant is native to Mexico and Central America,[3] where it is called sandita : ‘little watermelon’, from sandÃa : ‘watermelon’. It is believed to have been a domesticated crop before Western colonization of the Americas began.
These plants are slow-growing when they are establishing themselves, but can eventually grow up to 3 metres (9.8 ft) under proper conditions. They are drought resistant and pest-resistant relative to other cucumbers.[4] Similar to the cucumber, these plants are monoecious, producing both male and female flowers on the same plant. These plants can pollinate themselves, but the individual flowers are not self-fertile. Flowers are small and yellow, about four millimeters in diameter. Fruits develop at the base of the female flower.