Mitogenome analysis of a green tide forming from California, USA confirms its identity as (Ulvaceae, Chlorophyta).

An unknown species of marine sea lettuce was observed forming green tides consecutive years from 2014 to 2016 in Seaside, California. This sp. was similar in thallus size and shape to . To confirm this identification, whole genome sequencing was performed on the bloom-forming species of and the holotype specimen of . The complete green tide mitogenome is 64,143 bp in length, contains 65 genes, and displays high gene synteny with Kjellman. The mitogenome was incomplete for the holotype of , but the analysis yielded the mitoexome, plastid, and nuclear genetic markers. These data verify that the native is responsible for the blooms in central California.