ProtophytePro"to*phyte\, n. [Proto- + Gr. ? a plant.] (Bot.) Any unicellular plant, or plant forming only a plasmodium, having reproduction only by fission, gemmation, or cell division. Note: The protophytes (Protophyta) are by some botanists considered an independent branch or class of the vegetable kingdom, and made to include the lowest forms of both fungi and alg[ae], as slime molds, Bacteria, the nostocs, etc. Cf. Carpophyte, and O["o]phyte.