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The family Ericaceae is eurypalynous enough to clarify the differentiation of species and genera, but has limited potential for clarification of the demarcation and relationships of higher taxa (e.g. tribes). Generally, the recent classifications and relationships among the genera of Ericaceae were supported by results of the present study. Qualitative palynological characters (e.g., exine sculpture) were found to be taxonomically more important than quantitative characters (e.g., tetrad diameter), and various palynological characters important for different taxonomic levels. Palynological features were also found to be significant in some infrageneric classifications (e.g., Enkianthus, Arctostaphylos etc.), and to identify the monophyly of taxa (e.g., Dimorphanthera). Moreover, some taxonomic problems were presented, and realignments of some taxa have been suggested from the palynological view point, e.g. tribal limits of the tribe Bejarieae. Individual generic status of the following three taxa has been proposed: Erica recurvifolia E.G.H. Oliv. as Eremia recurvata Klotzsch; Rhododendron tsusiophyllum Sugim. as Tsusiophyllum tanakae Maxim.; and Vaccinium japonicum Miq. as Hugeria japonica (Miq.) Nakai. At least one misplaced species was also identified; Enkianthus sikokianus (Palibin) Ohwi should be recognized as a separate species, but it has been incorporated into E. campanulatus (Miq.) Nicholson. The present study revealed a number of evolutionary trends in different palynological features viz., pollen dispersal units, compactness of tetrads, pollen size and shape, aperture number and exine sculpture, within the family Ericaceae as well as within a genus (e.g. Enkianthus), and suggestions were made concerning the selective value of some of these trends. There is no clear correlation between pollen features of the family Ericaceae and either pollinators or geographical distributions, but present in lower taxa (e.g. Rhododendron, Erica). In the course of the pollen survey the following interesting discoveries were made: the first unique palynological feature – pollen tetrads without septa for the Ericaceae (e.g. Ceratostema) as well as other angiosperm families; the parallel evolution of pseudomonad pollen tetrad development in the subfamily Styphelioideae and Vaccinioideae; and pollenkitt ropes were found on the dried herbarium specimens (e.g. Notopora).

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