Morphological relationships within the genus Lophocladia (Rhodomelaceae, Rhodophyta) including a description of L. kuesteri sp. nov. from Hawai‘i

Abstract

Abbott I.A., Ballantine, D.L. and O'Doherty, D.C. 2010. Morphological relationships within the genus Lophocladia (Rhodomelaceae, Rhodophyta) including a description of L. kuesteri sp. nov. from Hawai‘i. Phycologia 49: 390–402. DOI: 10.2216/09-81.1The red alga Lophocladia kuesteri (tribe Lophothalieae, family Rhodomelaceae) from the Hawaiian islands is newly described and compared to the type species of the genus, L. trichoclados (Mertens ex C. Agardh) Schmitz. Newly observed features of stichidial structure in L. trichoclados show that primary stichidia may bear one or two secondary stichidia, these in turn capable of producing one or more tertiary stichidia. Sterile filaments near the apices of a few of the tertiary stichidia represent the first report of their occurrence in the genus. Spermatangial structures in Lophocladia kuesteri are stalked and originate from proximal trichoblast cells or, more distally, as lateral branchlets of trichoblasts. Procarps form on the suprabasal segments of trichoblasts and before fertilisation consist of a four-celled carpogonial branch with a short trichogyne and a single sterile cell group, the first report of this feature for the genus. Procarps are surrounded prior to fertilisation by a broadly based pericarp. Cystocarps are often as wide as tall, the ostiole lips scalloped or nearly circular at the end of a protruding carpostome. Molecular analyses support the inclusion of both the new Lophocladia species and L. trichoclados in the tribe Lophothalieae.