Abstract
1. The author investigated the pollen morphology of 121 species of Ericaceae, belonging to 24 genera (Japan 16 g. 82 sp., Kuril Arch. 9 g. 9 sp., Saghalien 7 g. 8 sp., Korea Pen. 2 g, 6 sp., Ryukyu Arch. 3 g. 5 sp., Formosa 4 g. 14 sp.) and 18 species of Pyrolaceae, belonging to 4 genera (Japan 4 g. 10 sp., Kuril Arch. 1 g. 1 sp., Saghalien 1 g. 1 sp., Korea Pen. 1 g. 2 sp., Formosa 2 g. 4 sp.). 2. The diameter of the tetrads varies from 20 μ in Arcterica nana (Fig. 82) to 77 μ in Rhododendron pentaphyllum (Fig. 40). 3. Rhododendron boninense (Fig. 74) and Chimaphila umbellata (Fig. 140) have the loosely attached tetrads and represent intermediate forms between tetrads and single grains. 4. The fine structure of the pollen wall and the viscin strands were investigated.
