Abstract
Type specimens of several taxa in the red algal family Delesseriaceae (Ceramiales), occurring in southern California and/or the Gulf of California, have been examined with particular attention to the anatomy of the apices and the development of the cell rows. On the basis of observations that the lateral pericentral cells do not undergo transverse divisions, that intercalary divisions occur in second-order cell rows, and the fact that bladelets can arise from the midline, Membranoptera spatulata Dawson and Hypoglossum gregarium Dawson [= Phrix gregarium (Dawson) Stewart] are demonstrated to be conspecific and to belong to the genus Apoglossum. The new combination A. gregarium is made. Apoglossum punctatum Dawson is recognized to be a taxonomic synonym of the earlier described Grinnellia lanceolata Dawson.
