Pollen grains of 40 taxa of Rhododendron L. and its closely related genera,
Therorhodion L. and Menziesia Sm., were examined by means of light microscopy and
scanning electron microscopy (SEM), or SEM alone. Pollen tetrads of R. japonicum, R.
schlippenbachii, R. tsusiophyllum and M. pentandra were examined also with
transmission electron microscopy