The 18S rRNA gene sequences of four commercially important seaweeds

18S rRNA gene sequences are presented forAhnfeltia plicata, Chondrus crispus, Furcellaria lumbricalis andPalmaria palmata, commercially important marine algae of the North Atlantic. The sequences range from 1765 to 1777 nucleotides in length, with guanine + cytosine content of 50.1% to 52.4%. Sequence divergence between species in different orders was 11.3–12.3%, whereas the variation betweenC. crispus andF. lumbricalis, both from the Gigartinales, was only 3.6%. Based on limited experience with other groups of Rhodophyta, these sequences obtained from single populations are likely to be representative of the species as a whole, with little variation expected among conspecifics regardless of morphological aberration or apparent genetic isolation.NRCC 34824.