Hormidiella M.O.P.Iyengar & Kanthamma, 1940
Holotype species: Hormidiella parvula M.O.P.Iyengar & Kanthamna
Original publication and holotype designation: Iyengar, M.O.P. & Kanthamma, S. (1940). Hormidiella, a new member of the Ulothrichaceae. Journal of the Indian Botanical Society 19: 157-166, 35 figs, pl. V [5]: figs 1-7.
Request PDFDescription: Filaments unbranched, uniseriate, attached to substratum by thin, hyaline, filiform holdfast projecting from the polar end of narrowed basal cell. At site of attachment holdfast ending in several minute ramifications. Apical cell broadly rounded. Cells cylindrical or dolioform, uninucleate. Chloroplast single, parietal, laminate to girdle-shaped, extending full cell length and almost completely encircling cell circumference, with one pyrenoid. Asexual reproduction by biflagellate zoospores formed singly in each cell except differentiated basal cell. Zoospores dorsiventral, containing posterior cup-shaped chloroplast with 1-2 pyrenoids and indistinct stigma. Flagella with subapical asymmetrical insertion towards ventral side of zoospore. After quiescence zoospores directly developing a filiform holdfast. Sexual reproduction by biflagellate gametes, arising one per cell and morphologically like zoospores. After a short period of swarming macrogametes becoming immobile, attaching, losing flagella, and rounding up. After enlargement and cell wall formation, one egg (an oogonium?) differentiates. Microgametes motile after release. Entrance of microgamete through ruptured wall of enlarged, mature macrogamete (oogonium?) followed by fusion. Spherical zygotes generally becoming surrounded by two-layered echinulate wall, producing 4 biflagellate zoospores after brief dormancy.
Information contributed by: G.M. Lokhorst; adapted from the original description.. The most recent alteration to this page was made on 2024-04-02 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Bierenbroodspot, M.J., Darienko, T., de Vries, S., Fürst-Jansen, J.M.R., Buschmann, H., Pröschold, T., Irisarri, I. & de Vries, J. (2024 '2023'). Phylogenomic insights into the first multicellular streptophyte. Current Biology 34: [1-12].
Comments: Hormidiella is known only from India, developing spontaneously in culture from soil, also from temporary ditch in rain water. Hormidiella is similar to Ulothrix (chloroplast) and Klebsormidium (shape of zoospores), however, unusual holdfast and specialized sexual reproduction justify establishment of Hormidiella.
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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=45650
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 02 April 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024
