Desmids

Desmids, a group of chlorospermous algae, in many respects resembling the brownish and siliceous diatoms (q.v.). They occur in pools and streams, and consist typically of loosely-connected chains of unicellular joints, or individuals, increasing, as in diatoms, by each pair of joints producing two new half-joints between them, and so on, each joint consisting of an older and a newer half. The chlorophyll which they contain is often confined to stellate or banded portions of the protoplasm. Conjugation takes place in many forms, either on contact or by the putting out of tubes, and results in the formation of a large resting-spore. Desmids have no known economic application.