Abstract
The chloroplast pigments of 12 spp. native to the marine waters of Australia were isolated by chromatography. All but one contained the same pigments found in the siphonalean Chlorophyceae of the Northern Hemisphere. Caulerpa filiformis lacked the siphonaxanthin and siphonein associated with the chlorophylls and carotenoids in the other Siphonales, but it contained a preponderance of a-carotene relative to [beta]-carotene as did all the other Siphonales. 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. The pigment distribution supports the classification of the Siphonales with the Chlorophyceae, the Heterosiphonales (Vaucheriaceae) and the Heterotrichales (Tribo-nemataceae) with the Xanthophyceae or Heterokontae.