Conferva

noun

1. A genus in which the older botanists placed many very heterogeneous species of filamentous cryptogams.
2. [lowercase; pl. confervæ (-vē).] The common name of plants of this genus.
3. Any unbranched, slender, green plant of the fresh-water algae. The word is frequently used in a wider sense.
4. An unbranched slender green freshwater alga.
5. any of various algae of the genus Tribonema; algae with branching filaments that form scum in still or stagnant fresh water