Malleodendron Pascher, 1937 '1939'

Holotype species: Malleodendron gloeopum Pascher

Publication details: Pascher, 1937 '1939': 301

Original publication and holotype designation: Pascher, A. (1937). Heterokonten. In: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. (Rabenhorst, L. Eds) Vol. 11(2), pp. 161-320. Leipzig: Akademische Verlagsgesellschaft.

Description: Unicellular, attached organisms becoming colonial with age and reaching 20-60 &m tall. Colonies branched, each branch with a single terminal cell; branching dichotomous except in the case of irregular development. Cells 8-18 &m long and 4-11 &m wide. The cell or colony supported by a cylindrical mucilaginous style that is sometimes stratified or crumpled, the same diameter as the cell and sometimes brown at the base from impregnation with iron salts. The cell is partly enclosed in the free concave tip of the style. Ellipsoid to ovoid, it is devoid of cell wall but is often bordered with a fine mucilaginous pellicle. Chloroplasts one to three, parietal and lamillate, without pyrenoids and brownish-green to olive. Two contractile vacuoles present at the anterior end of the cell, immersed in the style. Stigma absent. Vegetative reproduction by longitudinal division of cells. The two daughter cells secrete a new mucilaginous style of similar diameter to the cell and generate the branches which lengthen by successive deposition of additional mucilage. After division the daughter cells can also transform into zoospores with two unequal flagella (the largest is one and a half times the length of the cell), two or three (rarely one) chloroplast, two contractile vacuoles and possibly a stigma. Zoospores ovoid but often deformed by weak amoeboid movement. They attach after a short swimming period, produce a terminal mucilaginous cushion and secrete a firm gelatinous style. Cysts have never been observed. Malleodendron attached to other algae , debris and brackish mud; reported from central Europe and the eastern United States. Species distinguished based on the general form of the colony, the form and dimensions of cells and on chloroplast number. . caespitosum Thompson in Smith (1950) requires a more precise description than one based on habitat.

Information contributed by: A. Couté & C. Cardinal-Legrand. The most recent alteration to this page was made on 2021-10-04 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: Kawai, H. & Nakayama, T. (2015). Introduction (Heterokontobionta p.p.), Cryptophyta, Dinophyta, Haptophyta, Heterokontophyta (except Coscinodiscophyceae, Mediophyceae, Fragilariophyceae, Bacillariophyceae, Phaeophyceae, Eustigmatophyceae), Chlorarachniophyta, Euglenophyta. In: Syllabus of plant families. Adolf Engler's Syllabus der Pflanzenfamilien. Ed. 13. Phototrophic eukaryotic Algae. Glaucocystophyta, Cryptophyta, Dinophyta/Dinozoa, Haptophyta, Heterokontophyta/Ochrophyta, Chlorarachnniophyta/Cercozoa, Chlorophyta, Streptophyta p.p. (Frey, W. Eds), pp. 11-64, 103-139. Stuttgart: Borntraeger Science Publishers.

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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=46485

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 04 October 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 06 June 2025