The genus was first described by Danish botanist Hans Christian Lyngbye in 1819, and the type species is Callithamnion corymbosum(Smith) Lyngbye.,
The genus has cosmopolitan distribution. Species are found in Europe (including Norway and Great Britain,), Australia, America (including Massachusetts, New York, North Carolina and Georgia), Newfoundland (Canada), Sri Lanka and South Africa.
The genus of Callithamnion has undergone 2 major changes in its history. Carl Nägeli (in 1861) transferred species without alternate branchlets to Antithamnion, Rhodochorton and Acrochaetium. Then Genevieve Feldmann-Mazoyer in 1941 created genus Aglaothamnion for species having uninucleate cells, zig-zag carpogonial branches and lobed groups of carposporangia, and re-circumscribed Callithamnion. Aglaothamnion is now sometimes regarded as a synonym of Callithamnion with insufficient evidence for separate evolutionary lines of development.
Description
Callithamnion species are a marine red alga that is monaxial (having only one axis) with free filaments and the thalli are usually small tufts.
They are also erect, up to 10cm tall, with irregular branching and have multinucleate cells.
In most species are gametophytes and sporophytes are found throughout the year, but are usually only fertile in the late summer and autumn.
12Whittick, Alan (1981). "Culture and field studies on Callithamnion hookeri (Dillw.) S. F. Gray (Rhodophyta: Ceramiaceae) from Newfoundland". British Phycological Journal. 16 (3): 289–295. doi:10.1080/00071618100650311.
↑Reddy, Maggie M.; Stegenga, Herre; Anderson, Robert J.; Bolton, John J. (6 October 2020). "An updated species inventory of Callithamnion sensu lato Rhodophyta, Callithamniaceae in South Africa with the description of Callithamnion africanum sp. nov". Phytotaxa. 461 (3). doi:10.11646/phytotaxa.461.3.1.
↑Carl Nägeli, 1861, Beiträge zur Morphologie und Systematik des Ceramiaceae. Sber. bayer. Akad. Wiss. Jb. 1861, Vol. 1, pp. 297–415, Plate 1.