EVENING PRIMROSE POLLEN. Pollen of evening primrose from the species Oenothera fruticosa, variety ´Fireworks´ colorized SEM, x 3 297, the line corresponds to 10 microns. This pollen is not known to be allergenic. Oenothera fruticosa Evening primerose Onagraceae Eudicotyledon Angiospermae Plant. Under a very high magnification of 3297x, this scanning electron micrograph SEM revealed some of the morphologic ultrastructure displayed by a pollen grain found within the dehisced, or split open, an