Abstract: The pollen morphology of 10 species and 1 variety in the genus AcerLinn. from NE China was examined under light microscope(LM) and scan-ning electron microscope (SEM). Pollen grains of the genus are subspheroidal or prolate. subcircular ornarrowly elliptic in equatorial view, 3-lobed-rounded in polar view. Polaraxis 20-40μm long, 3-colpate, colpi obvious. Exine usually striped, rarelyreticulate. The pollen grains of genus can be divided into two types from thematerials examined:(1) Mono maple type:[Exine striped, stripes 0.25-0. 50μm broad;(2) Ash-leaved maple type:Exine striped-reticulate, luminairregularly, usually long, about 3μm long. Murus 0. 7m broad. The observation made by the present authors supports the subdivision of Acer intothe subgenera Acer and negundo by many taxonomists based on the other morphological characteristics, and observation by the present authors is inaccordance with this view. The treatment of Acer mono Maxim. and Acertruncatum Bge. as two independent species is also supported by the pollenmorphology shown in the present work.

Key words: Acer, Pollen morphology, Taxonomic signififcance