Private User has messaged the managers of this profile, concerned that sheis not showing the correct mother; traditionally she is given as the daughter of Gruffudd ap Rhys and Gwenllian verch Gruffudd; we have her at the moment with an unknown mother.
Here is my precis of the issue:
The children of Gruffudd ap Rhys -- sorry, here he is -- Gruffydd ap Rhys -- are variously attested. And of course because he is one of the important historical figures in Welsh history, they show up not only in the genealogies but in the histories. Rhys is referred to specifically as the son of Gruffudd and Gwenllian, but usually Gruffudd's children are given simply as his.
Gwladys appears in "Brut y Tywysogion" ("Chronicles of the Princes") only as the sister of Rhys -- and this is ambiguous; it can mean full sister or half sister. Given the context, we understand that she must be Gruffudd'd daughter. Here is the relevant passage, from the 1860 edition done by John Williams ab Ithel, which helpfully (for most of us) has the Welsh on one side and the English on the other: https://archive.org/details/brutytywysogiono00cara/page/226
In this passage, Rhys ap Gruffudd has been visiting the English King Henry II down at Gloucester, taking with him an entourage that includes "Seisyll, son of Dyvnwal, of Gwent Uchcoed, the man who was then married to Gwladus, sister of the lord Rhys."
The translation is clear, and unproblematic. The interpretation of it is more problematic.
Now, none of this would usually be an issue. In medieval Wales, illegitimate children, if recognized by their fathers (which as far as I can tell they usually were, this being Wales, not England), had inheritance rights and the like, and many became famous in their own rights.
It was, usually, not a big deal who their mothers were, and the genealogies sometimes delineate the mothers and sometimes don't.
In this case it IS a big deal, however, because Gruffudd's wife Gwenllian is celebrated herself, having died in battle in 1136. Here she is: https://en.wikipedia.org/wiki/Gwenllian_ferch_Gruffydd
The Wikipedia article gives her three sons -- Rhys is specifically said to be her son in the Gwentian Chronicle, which is another version of the Chronicle of the Princes -- here you go: https://archive.org/details/brutytywysogiong00cararich/page/112 (this edition is edited variously by a host of people -- the intro is here: https://archive.org/details/brutytywysogiong00cararich/page/n403)
It also lists Gwladus as Gwenllian's daughter; the note takes you to Thomas Pierce's entry for her in the 1959 edition of the Dictionary of Welsh Biography -- here THAT is -- https://biography.wales/article/s-GWEN-FER-1100 -- and if you go on down to the bottom of the page you can see that his source is "A History of Wales: from the Earliest Times to the Edwardian Conquest" (London 1912) -- this was written by John Edward Lloyd.
AAAAND interestingly enough the first passage concerning Gwenllian's children does not mention Gwladys -- https://archive.org/details/historyofwalesfr02lloyuoft/page/434
And the second still mentions only her sons, though it says that its information is taken from Jesus College MS 20 -- look! I found a transcription for you! http://www.maryjones.us/ctexts/jesus20gen.html -- search on the page for Gwenllian, and she's the only hit.
No daughters. Just the sons.
At any rate.
I'm loath to change Gwladys and give her Gwenllian as a mother; if anybody can find a MS that says actually who her mother is, that would be great!