auxospore

Century Dictionary and Cyclopedia

1. n. In the Diatomaceæ, an enlarged individual, formed either asexually, by the growth of the protoplasm attended by renewal of the silicious envelop, or sexually, by the union of the contents of two separate cells.
2. n. The resting-spore of the diatoms. It may be formed in at least five different ways, the most common methods being the following: the valves of a single diatom open, the contents emerge, become inclosed in a thin membrane, and increase in volume;

Wiktionary

1. n. biology A reproductive spore in diatoms that is formed by the union of two cells