  Dendrites with developed sidebranches are numerically studied with a coupled
map lattice model. The competitive dynamics among sidebranches determines the
shape of the envelope. The envelope has a parabolic shape near the tip of the
dendrite and the envelope angle with respect to the main branch increases up to
45$^{\circ}$ finally. In an intermediate region, the envelope grows roughly in
a power law, however, the exponent increases gradually as a function of the
distance from the tip. The competitive dynamics among many branches is also
observed in a unidirectional growth from a linear seed, and it is compared with
the competitive dynamics of sidebranches.
