Gymnophycus, a new genus of Ceramiaceae (Rhodophyta) from eastern Australia
Huisman, J.M. and Kraft, G.T. (1983) Gymnophycus, a new genus of Ceramiaceae (Rhodophyta) from eastern Australia. Phycologia, 22 (3). pp. 285-294.
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Gymnophycus gen. nov. (Ceramiaceae, Rhodophyta) is a genus of two species of minute algae from eastern Australia. Plants consist of erect, alternate-distichously branched uncorticated axes. Procarps are formed on the subterminal cells of major axes, the carpogonial branch arising on the first of three pericentral cells, which also bears a sterile lateral cell. In G. hypsispermis sp. nov., from southern Queensland, axial growth ceases with initiation of procarps and carposporophytes are terminal. In G. hapsiphorus sp. nov., from Lord Howe Island, N.S.W., and One Tree Island, Queensland, growth of the lateral axis on the sub-hypogenous cell continues after procarp formation, displacing the carposporophytes laterally. Fertilization in both species appears to result in transfer of the zygote nucleus to either the third pericentral cell or the supporting cell, followed by fusion of the supporting cell with the third pericentral cell via a small connecting cell. These cells form a distinctive perforate arch at the distal end of the fertile axial cell and give rise to two gonimoblast initials which together produce up to seven gonimolobes of carposporangia. The hypogenous cell is also incorporated into the fusion product. Neither involucral nor any type of adventitious filaments are associated with the mature carposporophyte. Sessile tetrahedral tetrasporangia are produced in adaxial rows on lateral branches, and male gametophytes bear dense spermatangial heads in a similar position. Because of fusion cell and carposporophyte anomalies, Gymnophycus is only provisionally placed in the tribe Compsothamnieae, with which it shares vegetative and procarp features.
|Publication Type:||Journal Article|
|Publisher:||International Phycological Society|
|Copyright:||© 1983 Blackwell Scientific Publications|
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