Hymenocladiopsis R.L.Moe, 1986

Holotype species: Hymenocladiopsis crustigena R.L.Moe

Currently accepted name for the type species: Hymenocladiopsis prolifera (Reinsch) M.J.Wynne

Original publication and holotype designation: Moe, R.L. (1986). Hymenocladiopsis crustigena (Rhodymeniaceae), a new genus and species of marine Rhodophyceae from the Antarctic Peninsula. Phycologia 25: 1-9.

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Description: Thallus with an extensive crustose holdfast from which one to many erect, regularly or irregularly pinnate or palmate, flattened fronds arise. Structure multiaxial, cortex of one or two layers of small cells, medulla of large axially elongated, multinucleate cells separated when young by mucilage-filled spaces or cavities, especially at the center, bearing groups of secretory cells. In older parts spaces or cavities becoming filled with loose chains or dense nests of smaller, multinucleate cells. Gametangial plants probably dioecious. Spermatangial sori superficial, scattered, spermatangia cut off terminally or laterally from modified cortical cells. Procarpic, carpogonial branches in cortex, 3-celled, formed on a large supporting cell with one, or rarely two, 2-celled auxiliary cell branches, gonimoblast developing outwards from a fusion cell. Cystocarps ostiolate, scattered, never coronate, strongly protruding outwards, with a flat roof, most cells forming carposporangia in 2-3 lobes of different ages, tela arachnoidea absent. Tetrasporangia formed terminally from cortical filaments, scattered, not grouped in nemathecia or sori. Spores tetrahedrally or irregularly arranged.

Information contributed by: M.D. Guiry. The most recent alteration to this page was made on 2011-07-07 by Wendy Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Le Gall, L., Dalen, J.L. & Saunders, G.W. (2008). Phylogenetic analyses of the red algal order Rhodymeniales supports recognition of the Hymenocladiaceae fam. nov., Fryeellaceae fam. nov., and Neogastroclonium gen. nov. Journal of Phycology 44: 1556-1571.

Comments: In habit, Hymenocladiopsis crustigena resembles species of Hymenocladia (q.v.), from which it differs in the formation of intercellular medullary spaces. Secretory cells are not produced in Hymenocladia species except for H. kallymenioides where they are formed exclusively in the cortex. Tetrasporangia are developed in an intercalary position in Hymenocladia but are terminal in Hymenocladiopsis. Both genera are, however, largely found in the colder waters of the Southern Hemisphere. The combination of characters of terminal, tetrahedrally divided tetrasporangia occurring scattered in the cortex of a blade-like plant with intracellular, mucilage-filled spaces is unique amongst the genera of the Rhodymeniales (Moe 1986). Hymenocladiopsis crustigena grows at depths of 5-30 m along the Antarctic Peninsula as far south as northern Marguerite Bay and in the South Shetland and South Orkney Is. (Moe 1986).

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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: https://www.algaebase.org/search/genus/detail/?genus_id=42685

Citing AlgaeBase
Cite this record as:
Wendy Guiry in Guiry, M.D. & Guiry, G.M. 07 July 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 26 April 2024