  BPS states of N=2, D=4 Super Yang-Mills theories with ADE flavor symmetry
arise as junctions joining a D3-brane to a set of 7-branes defining the
enhanced flavor algebra. We show that the familiar BPS spectrum of SU(2)
theories with N_f <= 4 is simply given by the set of junctions whose
self-intersection is bounded below as required by supersymmetry. This
constraint, together with the relations between junction and weight lattices,
is used to establish the appearance of arbitrarily large flavor representations
for the case of D_{n>=5} and E_n symmetries. Such representations are required
by consistency with decoupling down to smaller flavor symmetries.
