Vegetative and reproductive morphology of Ganonema lubrica sp. nov. (Liagoraceae, Rhodophyta) from the Canary Islands

Abstract

The marine red alga Ganonema lubrica sp. nov. (Liagoraceae, Nemaliales) from the Canary Islands is described. Gametophytes are terete, lubricous, lightly calcified, and radial to irregularly paniculately branched. Axes consist of many (18-26) primary medullary filaments that give rise to cortical fascicles with subcylindrical or clavate basal cells. Spermatangia form dense clusters on subterminal cortical cells, displacing the terminal cell laterally. Carpogonial branches are straight, five to eight cells in length, and arise from inner cortical supporting cells in positions occupied by adventitious cortical filaments. The carpogonium divides transversely and the upper half gives rise to a compact subhemispherical carposporophyte. Sterile filaments are absent or arise from the suprasupporting cell and partially or completely surround the carpogonial branch. Gonimoblastic rhizoids sometimes are present. Ganonema lubrica differs from previously described species of Ganonema and of the Mucosae group of Liagora mainly in the architecture of carpogonial branches, the shape of the basal cell of cortical fascicles, the derivation of most sterile filaments from the suprasupporting cell, and the occasional production of rhizoids from the gonimoblast.