Title: Morphology and taxonomy of Thamnocarpus (Ceramiaceae, Rhodophyta) in southern Australia and east Africa
Abstract: Plants of Thamnocarpus (Ceramiaceae, Rhodophyta) from southern Australia are all recognized as Thamnocarpus gunnianus Harvey. Previous taxonomic confusion leading to the establishment of several species existed due to variation in thallus features (even within individual plants), to collections of incomplete, denuded, cast-up material and to a lack of good fertile plants. Thamnocarpus differs from Callithamnion mainly in vegetative features, and is characterized by a terete thallus densely corticated by fine filaments and a surface layer of small cells. Delicate, determinate branchlets are borne singly from each young axial cell. These are alternatelyor irregularly arranged, dichotomously or subdichotomously branched and, due to their fragile nature, are easily lost. Reproduction is similar to that of Callithamnion in that two auxiliary cells are formed, one from each of a pair of opposite pericentral cells borne near branch apices. One pericentral cell bears a 4-celled carpogonial branch, and both auxiliary cells are fertilized from the single carpogonium. Thus two carposporophytes are initiated. Although similar in some features to Callithamnion, Thamnocarpus must be regarded as generically distinct, and is placed in the tribe Callithamnieae of the Ceramiaceae.Thamnocarpus mollis sp. nov. is described from east Africa. Plants are soft and gelatinous in contrast to the firm, cartilaginous thallus of T. gunnianus, and they differ significantly in several taxonomic features.
Publication Year: 1992
Publication Date: 1992-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 4
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