Summary[edit] Description: Brongniartella mucronata, a red alga = Heterodasya mucronata. Date: 1921. Source: Freshwater and Marine Image Bank. Author: Hoyt, W.D. (1917–18). Bulletin of the United States Bureau of Fisheries, vol. 36, pl. CIX-4. published by the U.S.Government Printing Office in 1921. Permission(Reusing this file): public domain, both as US govt. work and as pre-1923, confirmed on source site. Acknowlegement of the Freshwater and Marine Image Bank is requested.