Gem squash
Gem squash (Cucurbita pepo var. pepo) is a variety, or family, of summer squash. It may have come from two wild types; Cucurbita texana seen in the southern and central United States and Cucurbita fraterna found in Mexico. The dark green round fruit, when fully ripe, is around the size of a tennis ball. The young fruit is often harvested before it is fully ripe when it has  a softer flavor.