Re: Semantics of /ud-/ vs/ /u.d.d.-/

There is obviously an historical interaction between "ud-" and "u.l" /
"ull-" --not to mention "uu.lh".

Etymological confusion in more directions than one seems to me inevitable.

I have yet to see an instance where "fly up", "arise", etc., is
semantically wrong, but as I puzzle at this, it seems to me likely
that some older form (that was once something more exotic) may have
been simplified to /ud-/, /u.d.d-/ or /udd-/.

There is certainly room for morphological and semantic confusion here
--and none of the dictionaries I've seen treat these terms
specifically enough, etc. --but then, it is likely that someone with
more interest in Vedic roots, etc., will know more than I (and care
more than I).

E.M.