Weis" "Ancestral Roots. . ." (54:33), simply identifies her as Joan - no parents given.
Cokayne's "Complete Peerage" (Badlesmere, p.372), calls her the "dau. of Ralph FitzBernard of Kingsdown, Kent (aunt and, in her issue, h. to Thomas [Lord] FitzBernard)" But see next note for a refutation.
G . EDWARD ALLEN posted to GEN-MEDIEVAL-L@@rootsweb.com on 26 Aug 1997 (in part):
Subject: Re: EDMUND MORTIMER and ELIZABETH DE BADLESMERE
"Sorry, GUNCELINE DE BADLESMERE did not marry Joan FitzBernard. CP volume in which FitzBernard appears, p.403, note b: "Genealogists have ignored the fine of 6 Edw. II altogether and assert that these persons were the heirs of line to JohnFitzBernard, as descended from one Margaret, whom they variously describe as daughter or as aunt of Thomas FitzBernard, and mother of BARTHOLOMEW [it would appear that Joan is substituted for Margaret] de Badlesmere. The first statement, which is the older version, is clearly impossible; the other appears to be merely an arbitrary alteration of it, to make it possible: at all events, no evidence is produced. Nor is anything known about the wife of GUNCELIN, father of BARTHOLOMEW DE BADLESMERE. Moreover, it is not likely that Thomas, by a fine, would have given the reversion of the manor to the actual reversioner. What he did was to entail the manor on the heirs of his body, giving his wife a life interest, and then sell the manor to BARTHOLOMEW, knowing that his wife could recover it after his death: which she did, but not from BARTHOLOMEW, who had already lost the manor---and his life."
http://www.nelsonfamilyhistory.org/lee/5956.htm Joan married Gunselin de Badlesmere, son of Giles de Badlesmere and Margaret Leveland, about 1274 in Badlesmere Castle, Kent, England. (Gunselin de Badlesmere was born in 1244 in Badlesmere Castle, Kent, England, died in 1301 in Badlesmere Castle, Kent, England and was buried in Badlesmere, Kent, England.) Joan also married John - Baron de Wake. (John - Baron de Wake was born about 1232 in Blisworth, Northampton, England and died in 1300 in Blisworth, Northampton, England.)