Zucchini, also called courgette, and yellow squash, also called straightneck squash, are two common types of summer squash that are popular in the United States. Although squash are native to the Americas, cultivation of the squash that we know as zucchini was developed in Italy. Zucchini is the immature fruit of the squash variety called marrow in English. Zucchini and other summer squashes are harvested before they are fully matured, and they still have a tender and edible rind. Because the rind has not fully matured, summer squashes tend to have a short shelf life. Despite being derived from plants native to the Americas, zucchini was like brought to the United States by Italian immigrants in the early 20th century.