Maca is the only member of its genus with a fleshy hypocotyl , which is fused with the taproot to form a rough inverted pear-shaped body . Maca does vary greatly in the size and shape of the root , which may be triangular , flattened circular , spherical , or rectangular , the latter of which forms the largest roots . Traditionally , native growers have acknowledged four varieties of maca , based on their root color : cream-yellow , half purple , purple , and black ; varying levels of anthocyanin is primarily responsible for the color differences.  Maca hypocotyls may be gold or cream , red , purple , blue , black , or green . Each is considered a « genetically unique variety », as seeds of the parent plants grow to have roots of the same color . Specific phenotypes ( in maca , ‘ phenotype ’ pertains mainly to root color ) have been propagated exclusively to increase commercial interest.  Cream-colored roots are the most widely grown and are favored in Peru for their enhanced sweetness and size . Black maca is both sweet and slightly bitter in taste .