Euptilota (Ceramiaceae, Rhodophyta)
A morphological study and taxonomic revision of
A reassessment of the genus Euptilota reveals that it presently contains four validly published species: E. formosissima (Montagne) Kützing from New Zealand and the islands of the Campbell Plateau, E. articulata (J. Agardh) Schmitz from Australia, India, South Africa and Japan, E. fergusonii Cotton from the Indian Ocean, and E. molle (Wollaston) comb. nov., from the eastern part of South Africa. Euptilota pappeana Kützing from the Western Cape Province, South Africa, and E. mooreana Lindauer from New Zealand are excluded from the genus. Euptilota is characterized by: alternate-distichous branching at the apex, a prominent central axis covered by a small-celled outer cortex and with internal rhizoidal filaments, spermatangia with a terminal nucleus subtended by a single mucilage-containing vesicle, and fertile female periaxial cells borne in the plane of lateral branching. The carpogonium does not divide after fertilization and produces two tubular protuberances that are cut off as connecting cells. Traditionally placed in the tribe Ptiloteae, Euptilota appears to be more closely related to the Callithamnieae. As in the Callithamnieae, periaxial cells are cut off longitudinally in pairs from the fertile axial cell. One of each pair bears a horizontally oriented four-celled carpogonial branch and both cut off auxiliary cells after fertilization. Sterile group cells are absent. Connecting cells mediate transfer of the derivatives of the fertilization nucleus to the auxiliary cells. A diploid nucleus divides at the surface of an auxiliary cell and one daughter nucleus moves to its centre while the other is extruded into a residual cell. The haploid auxiliary cell nucleus is cut off into a foot cell. It is proposed that the closest relatives of Euptilota are Seirospora and Sciurothamnion.