Myosotis scorpioides L. produces one of the smallest pollen grains. To date, the morphology and structure of the sporoderm of these grains have been studied, but the ultrastructure of their protoplasts has not been sufficiently investigated. The aim of the study was to analyse the structure of the anther wall, determine the tapetum type, and examine the size and subcellular aspects of M. scorpioides pollen grains. The study was carried out with the use of light, scanning, and transmission electron microscopy techniques. In the pollen maturity phase, the epidermis, the endothecium with reinforced walls, and the remains of the middle layer and cell walls of the plasmodial tapetum were distinguished in the anther wall. The characteristic traits of M. scorpioides anthers include the plasmodial tapetum and the presence of polygonal orbicules. Plasmodial tapetum protoplasts were observed in close proximity to the pollen grains. The orbicules, fused with the sporoderm, were present in both the tapetum cell remains and on the surface of the pollen grains. The length of the polar and equatorial axes of the grains was 7.5 µm and 3.2 µm, respectively. The subcellular characteristics of the pollen grains included a vegetative cell with a lobulated nucleus, numerous plastids surrounded by a rough endoplasmic reticulum, numerous mitochondria, rough endoplasmic reticulum profiles, various-sized vesicles, highly numerous ribosomes, and two sperm cells with a small amount of cytoplasm. The plastids and mitochondria were spherical and substantially smaller than those present in somatic cells.