Acorn squash (Cucurbita pepo var. turbinata), also called pepper squash or Des Moines squash, is a winter squash with distinctive longitudinal ridges on its exterior and sweet, yellow-orange flesh inside. Although considered a winter squash, acorn squash belongs to the same species (Cucurbita pepo) as all summer squashes (including zucchini and crookneck squash). Indigenous to North and Central America, the squash was introduced to early European settlers by Native Americans.