Askelpios does sometimes lean on the staff that is couched in
his armpit, but, as you observe, on many coins it is only propped against
his side; also, on the
cistophori and on small bronzes of
Pergamon, we see the staff, or the so-called 'temple key', by itself with the
snake entwining it. Just to start discussion, since someone else may have read dissertations on it, I have thought that a staff is normal for handling a familiar
snake. A
snake wants to climb up something. In a jungle he'll climb up vines or trees.
Hygieia has hers use her own body, but, for whatever reason,
Asklepios does not;
his climbs the staff. We also see Athena's spear and sometimes another goddess's
scepter entwined with her
snake. Athena's Erichthonios
snake climbs the Acropolis olive tree, and the guardian of the apples of immortality climbs the tree that bears them. For a mantic
Apollo, the tripod or a tree may serve; indeed, a tripod alone often serves.
Pat L.