mayhaw

from The Century Dictionary.

• noun A small tree, Cratægus æstivalis, of the southern United States. Its fruit, which ripens in May, is used for preserves, jellies, etc. Also apple-haw.
• noun This species has the largest flowers and the largest and best-flavored fruit of the genus. In southwestern Louisiana the fruit is largely gathered for the market, being utilized for jellies, etc. Also called summer haw.

from the GNU version of the Collaborative International Dictionary of English.

• noun The hawthorn tree (Crataegus aestivalis) of the Southern U. S. bearing a juicy acid scarlet fruit often used in jellies or preserves.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun hawthorn of southern United States bearing a juicy, acidic, scarlet fruit that is often used in jellies or preserves