Studies in the Liagoraceae (Nemaliales, Rhodophyta) I. The genus Trichogloea

The calcified, though strongly mucosoid gametophytes of Trichogloea (Nemaliales, Liagoraceae) usually appear seasonally for a short period in tropical and subtropical regions. Vegetative and reproductive characteristics of the presently recognized species, Trichogloea requienii (Mont.) Kützing (the generitype), Trichogloea lubrica J. Agardh, and Trichogloea herveyi W. R. Taylor, are described and compared. In addition, the identities of two previously synonymized species, Trichogloea jadinii Børgesen and Trichogloea javensis B0rgesen are clarified. Species of the genus display considerable variation in habit and branching patterns, necessitating an assessment of reproductive structures for accurate identification. Reliable features of Trichogloea include the structure of the medulla and the cortical (assimilatory) filaments, location and structure of carpogonial branches and spermatangia, and the nature of sterile filaments in the vicinity of the cystocarp. Secondary features include both external and internal branching pattern, and the proportion of calcium carbonate to lubricous material, the latter having to be assessed from fresh collections. The present study provides a comparative morphological account of the species of Trichogloea. As a result, T. requienii, T. lubrica, T. herveyi are confirmed as independent species; T. jadinii is removed from synonymy with T. lubrica and placed in that of T. requienii, and T. javensis is confirmed as a synonym of Izziella orientalis (J. Agardh) Huisman et Schils.