On the page for Mary Berkeley wife of Malcolm, Earl Angus (d bef 1242) there are no parents shown for Mary.
In "Living Descendents of Blood Royal" by Count d'Angerville, World Nobility and Peerage, ed. [1962?], p 449 in the article on Hunt-Kelly he states:
"11 Elizabeth Comyn, d bef 17 Feb 1328/9; m Gilbert de Umfreville, b 1244, d bef 13 oct 1307, Baron Umfreville, Earl of Angus, M.P., 1296-1307, son of Gilbert de Umfreville and Maud, dau of Malcolm, Earl of Angus by Mary, dau. of Sir Humphrey Berkeley."
Unfortunately, 11 has no particular citation to the underlying source.
Will Johnson