#diatoms

• Actinella — Romanian name adapted from the taxonomic genus Actinella. In botany, it defines a genus of herbaceous plants (often associated with Hymenoxys) in the Asteraceae family, or a genus of unicellular algae (diatoms) characterized by asymmetric, arched siliceous shells that expand radially at one extremity. In micropaleontology, these fossilized structures are used as environmental indicators.
• Auxospore — A specialized reproductive cell or growth spore formed as a result of sexual reproduction (or autogamy) in unicellular phytoplanktonic algae of the diatom class (Bacillariophyceae); this spore expands considerably in volume to restore the original size of the species, compensating for the progressive reduction of the siliceous frustule that occurs during successive asexual divisions.
• Diatoms — A class of microscopic unicellular or colonial algae, scientifically known as Bacillariophyceae or commonly as diatoms, characterized by a silicified, rigid, and ornamented cell wall called a frustule, consisting of two overlapping valves like a box. These aquatic photosynthetic organisms play a fundamental ecological role as primary producers in the phytoplankton of seas and fresh waters, with their fossil accumulations forming diatomite.