Pigment Composition of the Scaly Green Flagellate Mesostigma Viride (Micromonadophyceae) Is Similar to That of the Siphonous Green Alga Bryopis Plumosa (Ulvophyceae)1

Pigments were isolated from Mesostigma viride Lauterborn by reversed‐phase high‐performance liquid chromatography and compared to standards from Chlamydomonas reinhardtii Dang. and Bryopsis plumose (Huds.) Ag. M. viride possesses chlorophylls a and b, α and β‐carotenes, and the xanthophylls siphonaxanthis, siphonein, neoxanthin, violaxanthin and echinenone. In addition, three unidentified xanthophylla were detected. Neither lutein nor zeaxanthin were detected. The pigment composition of M. viride was similar to that of B. plumosa which had chlorophylls a and b, ɛ‐ and α‐carotenes, siphonaxanthin, siphonein, neoxanthin, violaxanthin, and two of the unidentified xanthophylls found in M. viride. The similarities in the pigments of Mesostigma and Bryopsis and other characters suggest that Mesostigma may be related to a flagellate ancestor of the Ulvophyceae.