Taenioma J.Agardh, 1863

Holotype species: Taenioma perpusillum (J.Agardh) J.Agardh

Original publication and holotype designation: Agardh, J.G. (1863). Species genera et ordines algarum, seu descriptiones succinctae specierum, generum et ordinum, quibus algarum regnum constituitur. Volumen secundum: algas florideas complectens. Part 2, fasc. 3. pp. 787-1138, 1158-1291. Lundae [Lund]: C.W.K. Gleerup. [in Latin]

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Description: Thalli of small size (a few millimeters high), often forming mats of hairy tufts, with parts both prostrate, not corticated, fixed to the substratum by unicellular rhizoids, either erect, made up of exogenous branches, either cylindrical with indeterminate growth, or flattened with growth determined; the latter are monostromatic, equipped with a tristromatic midrib and typically terminated by 1-5 long, segmented, colorless, persistent hairs and each equipped with a basal meristem connected by synapses directly to the axial cell. The axes and branches with indeterminate growth have apical growth by means of an evident bell-shaped cell with transverse division; from this the filament of axial cells originates which produces 4 periaxial cells per segment; the first 2 periaxial cells separate respectively to the right and left of the axial cell and are called lateral cells; while the other 2, separated anteriorly and posteriorly from the axial, are called ventral and dorsal respectively. In the flattened branches with determined growth, the lateral periaxials divide further to each form 2 marginal cells (flanking cells) which in turn can divide to each form a transverse row of 2-4 cells all on the same plane as the 2 lateral periaxials; the ventral and dorsal periaxial remain undivided. Rare gametophytes, generally dioecious. Spermatocysts grouped in sori carried on the two surfaces of the flattened branches with determined growth; the sori develop between the midrib and the branch margin. Procarps and cystocarps on branches with indeterminate growth; the procarpals are composed of a carpogonial branch of 4 cells and 2 groups of sterile cells; the cystocarps have a basal fusion cell and the carposporocysts in short chains within an urceolate pericarp with ostiole. The tetrasporocysts, with tetrahedral division, are carried in a single layer, 2 per article, so as to form two longitudinal rows in acropetal succession on the sides of the median rib of the flattened branches with determined growth; after the fertile periaxial cell has produced the initial tetrasporocyst, it divides again twice with walls parallel to the surface to form two small and rudimentary cell coverts, one for each face of the fertile branch.

Information contributed by: Cormaci & al. (2023: 556-7).. The most recent alteration to this page was made on 2023-12-11 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 neuter.

Most recent taxonomic treatment adopted: Wynne, M.J. (2014 '2013'). The red algal families Delesseriaceae and Sarcomeniaceae. pp. [1]-326, 118 figs. Königstein: Koeltz Scientific Books.

Comments: The following two species are reported in the Mediterranean: T. nanum and T. perpusillum. However, since the presence of the latter species in the Mediterranean is to be confirmed, it has been included in the identification key, but briefly treated only in the note to the genus.

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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=33314

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 11 December 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024