Notes on Rhodomelaceae (Rhodophyta) from the Canary Islands: Observations on reproductive morphology and new records

Abstract

Sexual plants in the monotypic genus Ctenosiphonia Falkenberg and in two species of Polysiphonia Greville [P. subulifera (C. Agardh) Harvey and P. flexella (C. Agardh) J. Agardh] are described for the first time in material collected from the Canary Islands. In Ctenosiphonia hypnoides (J. Agardh) Falkenberg cylindrical spermatangial axes replace both branches at the second dichotomy of fertile trichoblasts. The procarps arise on the second basal segment of a fertile trichoblast and consist of a 4-celled carpogonial branch, and two sterile-cell groups are borne on the supporting cell. Up to ten cystocarps are arranged in a series on the dorsal side of erect branches. Both Polysiphonia subulifera and P. flexella show spermatangial axes formed at the first dichotomy of fertile trichoblasts, replacing one branch and ending in 122 sterile terminal cells. Cystocarps are globose to pyriform in P. subulifera and spherical and flattened in P. flexella. Two species of Rhodomelaceae: Polysiphonia tepida Hollenberg and Womersleyella setacea (Hollenberg) R. E. Norris, and Aiolocolax pulchellus Pocock, related to Rhodomelaceae but of uncertain systematic position, are reported from the Canary Islands for the first time. Data concerning ecological conditions, geographical distribution, morphology and phenology are presented.