Hypnea J.V.Lamouroux, 1813: 131

Classification:
Empire Eukaryota
Kingdom Plantae
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Rhodymeniophycidae
Order Gigartinales
Family Cystocloniaceae

Lectotype species: Hypnea musciformis (Wulfen) J.V.Lamouroux

Original publication:Lamouroux, J.V.F. (1813). Essai sur les genres de la famille des thalassiophytes non articulées. Annales du Muséum d'Histoire Naturelle, Paris 20: 21-47, 115-139, 267-293, pls 7-13.
Download PDF

Type designated inKylin, H. (1932). Die Florideenordung Gigartinales. Acta Universitatis Lundensis 28(8): 1-88, 22 figs, 28 plates.

Taxonomic status: currently recognized as a distinct genus.

notes
The Hypneaceae, questionably distinct from the Cystocloniaceae on anatomical grounds, were recently subsumed into the latter family by Saunders et al. (2004) based on small-subunit rDNA sequence studies. - (25 Jul 2006) -

Description: Plants are generally terete, erect or in entangled clumps, or minute parasites. Apices are uniaxial, and cross sections are pseudoparenchymatous throughout, the medulla surrounding the usually distinct central axial filament and in many species containing greater or lesser numbers of cells with lenticular secondary wall thickenings. Inner cells are multinucleate and linked by secondary pit connections. Female gametophytes are procarpic, the 3-celled carpogonial branches borne singly and laterally on inner cortical cells and directed thallus outwardly. Auxiliary cells are intercalary, borne directly distal to the supporting cell in the same cortical filament, and are diploidized by a short process or direct fusion with the fertilized carpogonium. The single gonimoblast initial is directed thallus inwardly. Cystocarps are protuberant, ostiolate or non-ostiolate, encased in a thick pericarp, and consist of a central sterile tissue of large isodiametric cells surrounded by radiating gonimoblasts ending in single, terminal carposporangia. A basal nutritive tissue generally subtends the gonimoblast. Spermatangia occur in clusters. Tetrasporophytes are isomorphic with gametophytes and produce zonate tetrasporangia in nemathecia or sori.

Comments: The Hypneaceae is a family of 1 free-living and 1 parasitic genus (Hypenocolax). As pointed out by Min-Thein and Womersley (1976), the Hypneaceae is virtually indistinguishable on present criteria from the family Cystocloniaceae, especially the genus Calliblepharis. The two families differ in the consistently single, rather than paired or chained, carposporangia of the Hypneaceae, and the tendency of most Hypnea species to be terete, rather than compressed or flattened. The species of Hypnea that have been tested produce kappa or kappa and iota carrageenans. This, plus the widespread tropical distribution and abundance of the species has led to great interest in their cultivation and harvesting in the northern and western Indian Oceans (Mshigeni 1978; Parekh et al. 1988; Dawes 1987). The Hypneaceae, questionably distinct from the Cystocloniaceae on anatomical grounds, were recently subsumed into the latter family by Saunders et al. (2004) based on small-subunit rDNA sequence studies.

NCBI Nucleotide Sequences

Numbers of names and species: There are 112 species (and infraspecific) names in the database at present, of which 54 have been flagged as currently accepted taxonomically.

Names: ('C' indicates a name that is currently accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

References
Saunders, G.W., Chiovitti, A. & Kraft, G.T. (2004). Small-subunit rRNA gene sequences from representatives of selected families of the Gigartinales and Rhodymeniales (Rhodophyta). 3. Recognizing the Gigartinales sensu stricto. Canadian Journal of Botany 82: 43-74.

Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=32938

Citing AlgaeBase
Cite this record as:
Guiry, M.D. & Guiry, G.M. 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 May 2013.

Algaebase taxon LSID: urn:lsid:algaebase.org:taxname:8299