Ditria Hollenberg, 1967
Holotype species: Ditria reptans Hollenberg
Original publication and holotype designation: Hollenberg, G.J. (1967). New genera in the Rhodomelaceae from the Central Pacific. Bulletin of the Southern California Academy of Sciences 66: 201-221, 15 figs.
Request PDFDescription: Prostrate branches 80-115 µ in diameter, composed of segments one diameter long or shorter, with moderately thick walls; lateral branches arising exogenously or cicatrigenously, commonly at intervals of 2 and 3 segments in alternating sequence. Chromatophores numerous 1.5-2.0 µ in diameter and arranged in forking chains or transverse bands; trichoblasts to 1.25 mm. long and 40-48 µ in diameter at the base, with 7-8 dichotomies.
Thallus small, mostly prostrate but with some erect determinate laterals, terete, all axes with 5 pericentral cells, ecorticate. Attachment by branched multicellullar rhizoids arising from ventral pericentral cells of the prostrate axes. Indeterminate axes bearing a branch primordium or lateral branch on every segment, these arising in a spiral sequence with lateral branches separated by alternating intervals of 1 and 2 dormant branch primordia (i.e. 2 and 3 segments). In one species (D. expleta) the laterals arising in alternate pairs, the pairs separated by intervals of 1 branch primordium (i.e. alternating intervals of 1 and 2 segments). Determinate branches arising mostly in a lateral position, appearing alternate and distichous. Apices of branches with branched trichoblasts. Spermatangia in heads, replacing trichoblasts. Procarps borne on trichoblasts, with a 4-celled carpogonial branch and 2 sterile groups. Carposporphyte with a fusion cell and terminal clavate carposporangia. Cystocarps ovate, terminal on determinate lateral branches. Tetrasporangia borne in a spiral sequence in determinate lateral branches, 1 per segment, tetrahedrally divided.
Information contributed by: Original description and Huisman (2018). The most recent alteration to this page was made on 2022-12-20 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.
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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=35648
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 December 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 26 November 2024
