  Ultracold collisions of the polyatomic species CaOH are considered, in
internal states where the collisions should be dominated by long-range
dipole-dipole interactions. The computed rate constants suggest that
evaporative cooling can be quite efficient for these species, provided they
start at temperatures achievable by laser cooling. The rate constants are shown
to become more favorable for evaporative cooling as the electric field
increases. Moreover, long-range dimer states (CaOH)$^*_2$ are predicated to
occur, having lifetimes on the order of microseconds.
