<![CDATA[Abstract. Saensouk S, Saensouk P. 2021. Pollen morphology of some species in family Amaranthaceae from Thailand. Biodiversitas 23: 601-611. The aim of this study was to study the pollen morphology of 14 species, eight genera from the family Amaranthaceae in Thailand by the applied acetolysis method and it was taken under light and scanning electron microcopies. All pollen grains had monad, radial symmetry and apolar. The pollens in this study can be divided into several groups based on shape, size, aperture, mesoporia, the character of aperture, and exine sculpturing. The sizes of the pollen can be divided into three groups, i.e., very small pollen group, small pollen group, and medium pollen group. The shapes of the pollen can be divided into three groups, i.e., spheroidal, pentagon, and dodecahedric. Exine sculpturing can be divided into three groups, i.e., granular, macrogranular, and microspine. The pollen in this study can be divided into five groups based on the character of the aperture, i.e., aperture with convex circular-like shape, aperture with deeply collapsed circular-like shape, aperture with collapsed circular-like shape, aperture with collapsed pentagon-like shape, and 6-angular element or hexagon-like shape. The pollen in this study can be divided into three groups based on the mesoporia, i.e., mesoporia broadly flat, mesoporia moderately and broadly vaulted, and mesoporia narrow and highly vaulted. The number of apertures was found to be between 12-54 apertures per pollen. The aperture diameters of Amaranthaceae pollen in this study ranged from 0.5-5 µm. The exine thickness of the pollen in this study was 1.12±0.04 - 2.14±0.31 µm. The pollen character of this study can be divided into eight types, i.e., Achyranthes-type, Alternanthera-type, Amaranthus-type, Celosia-type, Cyathula-type, Gomphrena-type, Ouret-type, and Psilotrichum-type. The pollen characteristic of Alternanthera pungens Kunth, A. Sessilis (L.) R. BR., Amaranthus blitum subsp. oleraceus (L.) Costea, Cyathula prostrate (L.) Blume., Ouret sanguinolenta (L.) Kuntze, and Psilotrichum ferrugineum (Roxb.) Voigt were reported for the first time.]]>
