Let
k
k
be an algebraically closed field and
A
A
be a finite-dimensional associative basic
k
k
-algebra of the form
A
=
k
Q
/
I
A=kQ/I
where
Q
Q
is a quiver without oriented cycles or double arrows and
I
I
is an admissible ideal of
k
Q
kQ
. We consider roots of the Tits form
q
A
q_A
, in particular in the case where
q
A
q_A
is weakly non-negative. We prove that for any maximal omnipresent root
v
v
of
q
A
q_A
, there exists an indecomposable
A
A
-module
X
X
such that v=dim X. Moreover, if
A
A
is strongly simply connected, the existence of a maximal omnipresent root of
q
A
q_A
implies that
A
A
is tame of tilted type.