The pollen morphology of six species of Keiskea and three representative taxa of Collinsonia was studied in detail using LM, SEM, and TEM. In both genera, pollen grains are monad, hexa-colpate, and mostly medium in size [P=28.0 to $37.0;{mu}m$, E = 24.3 to $30.7;{mu}m$ (Keiskea); P = 30.0 to $45.0;{mu}m$, E = 26.0 to $39.0;{mu}m$ (Collinsonia)]. Polar outlines are of circular or ellipsoid form. Shapes range from primarily oblate-spheroidal to prolate-spheroidal to subprolate, and rarely prolate in the equatorial view. Their exine, including the intine characters, are clearly distinct from each other: Keiskea, well-developed bi-reticulate, often forming large lumina by supratectal ridges, unbranched columellae, one-third to one-half of the total exine thickness; versus Collinsonia, mostly perforate without supratectal ridges or a faint/very weak bi-reticulate appearance without supratectal ridges, seemingly branched columellae, ca. two-thirds of the total exine thickness. As demonstrated by these current data, the pollen morphology of the two genera is well distinguished, easily supporting the separation of Keiskea from Collinsonia.