CHLOROPLAST PIGMENTS AND THE CLASSIFICATION OF SOME SIPHONALEAN GREEN ALGAE OF AUSTRALIA

1. The chloroplast pigments of twelve species of siphonalean green algae native to the marine waters of Australia were isolated by chromatography.2. All these siphonalean species but one contained the same pigments found in the siphonalean Chlorophyceae of the Northern Hemisphere.3. Caulerpa filiformis lacked the siphonaxanthin and siphonein associated with the chlorophylls and carotenoids in the other Siphonales, but it contained a preponderance of α-carotene relative toβ-carotene as did all the other Siphonales.4. These observations indicate that the Siphonales are significantly different from the other green algae, but they are more closely related to the Chlorophyceae than to any other algal group.5. The pigment distribution supports the classification of the Siphonales with the Chlorophyceae, the Heterosiphonales (Vaucheriaceae) and the Heterotrichales (Tribonemataceae) with the Xanthophyceae or Heterokontae.