Aglaothamnion priceanum sp. Nov. (ceramiaceae, rhodophyta) from the north-eastern atlantic: Morphology and life history of parasporangial plants

Authors: Maggs, C.A., Guiry, M.D. and Rueness, J.

Journal: British Phycological Journal

Volume: 26

Issue: 4

Pages: 343-352

ISSN: 0007-1617

DOI: 10.1080/00071619100650311

Abstract:

Aglaothamnion priceanum sp. nov. (Ceramiaceae, Rhodophyta) is described from Clare Island, Co. Mayo, Ireland (type locality), Scotland, the Faeroes, and north-western France, where it occurs in the subtidal of wave-exposed sites as a small epiphyte on species of Laminaria, on the red alga Meredithia microphylla, and on the tubes of serpulid polychaetes. The species was previously included with Callithamnion decompositum J. Agardh, but the holotype of C. decompositum is a plant related to Compsothamnion and does not correspond with any of the entities previously included under the name Callithamnion decompositum. Parasporangial plants collected from the type locality, and at Gjogv, Faeroes, gave rise in culture to further plants forming parasporangia. Although paraspores from the Clare Island first-generation cultured plants developed into healthy plants, no further parasporangia were produced under a range of temperature and daylength conditions. Optimal growth of the Faeroese strain was obtained at 12-17°C, growth was poor at 9-5°C, and plants did not survive at 6 and 20°C. Successive generations of parasporangial plants were obtained at 15°C and a chromosome count of at least 80 was obtained, suggesting the possibility that this species has a triploid complement of chromosomes. Aglaothamnion priceanum is 2-8 (֊ 20) mm in height with regularly alternate distichous branches, the first two cells of which generally bear an adaxial branchlet and the third cell an abaxial branchlet. Cells and parasporangia are uninucleate. Plants from Ireland, France and the Faeroes are described in detail. Although the genus Aglaothamnion has not gained universal acceptance since it was first proposed in 1941, its adoption is recommended for species with uninucleate cells previously referred to Callithamnion. © 1991 The British Phycological Society.

Source: Scopus