Cephaleuros Kunze ex E.M., 1832
Lectotype species: Cephaleuros virescens Kunze ex E.M.Fries
Original publication:Fries, E.[M.] (1832). Systema mycologicum: sistens fungorum ordines, genera et species, huc usque cognitas, quas ad normam methodi naturalis determinavit / disposuit atque descripsit. Volumen III et ultimum. pp. -524, -202 p. ["Index alphabeticus generum, ..."]. Grypiswaldae: Sumptibus Entestii Mauritii.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Thompson, R.H. & Wujek, D.E. (1997). Trentepohliales: Cephaleuros, Phycopeltis and Stomatochroon. Morphology, taxonomy and ecology. pp. [i-vii] viii-x, -149, 60 pls. Enfield, New Hampshire: Science Publishers, Inc.
According to INA, Fries cites "Kunz. in litt."; from kephale euros; name previously published by Kunze with Latin description on label to a specimen in an informal set of specimens distributed to various herbaria, probably in 1829, dubiously valid. While Cephaleuros virescens Kunze ex E.M.Fries is regarded as the type, we have not discovered who lectotypified it. - (10 Mar 2010) - M.D. Guiry
Description: Heterotrichous with filamentous to pseudoparenchymatous prostrate thallus and erect multicellular sterile or zoosporangia-bearing branches. Rhizoidal branches produced ventrally. Often forming orange to orange-red (due to cytoplasmic accumulations of carotenoids), velvet-like spots 10 mm or more in diameter. Branching dichotomous to pinnate, producing suborbicular thalli. Chloroplasts irregular parietal networks without pyrenoids. Nucleus single in vegetative cells. Central portion of intercellular cross walls with simple plasmodesmata. Structurally specialized cross walls between pedicel and zoosporangium with plasmodesmata located in central ring of thickened wall material.
Asexual reproduction by zoospores produced on fertile branches forming enlarged pyriform "head cells" producing, in turn, "sporangiate laterals" comprising short suffultory cell (or, neck cell, hook cell, stalk cell, pedicel, etc.) that bears an enlarged, ovoid zoosporangium (="Hackensporangium," ca. 21-36 m x 18-26 m) that abscises from suffultory cell by circumscissile tearing of outer wall and splitting of modified cross wall. Nipple-like protuberances from center of cross wall of both zoosporangium and suffultory cell may facilitate final abscission of zoosporangium. Zoosporangia not resistant stages and, if wet, release 8-64 quadriflagellate zoospores (ca. 8 x 3 &m with smooth, isokont flagella ca. 17 &m long) through distinctive pore-papillae. Zoospores form new thalli. Sexual reproduction isogamous. Gametangia ("Kugelsporangien") greatly enlarged terminal, lateral or intercalary cells of prostrate thallus that break through host cuticle and release hundreds of biflagellate gametes through dorsal pore-papillae. Gametes reported to fuse and produce dwarf sporophytes that form abscising meiosporangia that in turn produce quadriflagellate meiospores. Unmated gametes form new thalli. Reported alternation of anisomorphic generations not fully documented; life cycles may differ fundamentally between species.
Information contributed by: R. L. Chapman. The most recent alteration to this page was made on 22 Mar 2018 by M.D. Guiry.
Comments: Circumtropical and subtropical, epi- or endobiotic on leaves, fruits, and young stems of more than 200 species of vascular plant hosts. Species level taxonomy requires revision. Some species may grow intracellularly into host tissue often causing black spots; a nuisance organism on avocado, citrus, and ornamentals. Once considered a pathogen on coffee and tea plants (put possibly only opportunistic following fungal infections). Important studies of the late R. H. Thompson (from which the terminology and much of the basic information in this synopsis is derived) remain unpublished. The basis of host specificity unknown and nutritional relationships between alga and host not well studied.
All motile cells bear flagella with two lateral keels that effectively double the flagellum width in a plane perpendicular to the stroke of the flagella. Both gametes and zoospores with two multilayered structures (MLSs) closely associated with basal bodies. Both lack eyespots, scales and pyrenoids. Gametes with two areas of modifed cell membrane near apical papilla analogous to mating structures in Chlamydomonas. Top layer formed of microtubules extending porteriorly, producing two of four flagellar roots. MLSs similar to, but not necessarily homologous with, MLSs in Charophyceae and lower land plants. Higher plant-like phragmoplast formed in vegetative cell division of C. parasiticus. Although ultrastructural characters suggest affinity to Charophyceae, cladistic analysis of ribosomal RNA sequences supports placement in Ulvophyceae, suggesting early divergence of Trentepohliales in evolution of green algal lineages. Pelicothallos villosa Dilcher from Middle Eocene (ca. 44-52 Ma) only known fossil for Trentepohliales. Thallus preservation and sporangiate branches allows recognition of fossil as Cephaleuros. Sporopollenin in some Trentepohliales may contribute to preservation in more recent geological formations. Similar to Trentepohlia and Phycopeltis, Cephaleuros often lichenized.
English: Red rust (Duddington 1966).
Numbers of names and species: There are 29 species names in the database at present, as well as 2 infraspecific names. Of the species names, 19 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..
Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Click here to also show infraspecific names in the list below.
Brooks, F., Rindi, F., Suto, Y., Ohtani, S. & Green, M. (2015). The Trentepohliales (Ulvophyceae: Chlorophyta): an usual algal order and its novel plant pathogen, Cephaleuros. Plant Disease 99(6): 740-753.
Zhu, H., Hu, Z.Y. & Liu, G.X. (2017). Morphology and molecular phylogeny of Trentepohiales (Chlorophyta) from China. European Journal of Phycology 52(3): 330-341.
Nelson, S.C. (2008). Cephaleuros species, the plant-parasitic green algae. Plant Disease 43: 1-6.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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.
Created: 11 April 2002 by M.D. Guiry
Verified by: 22 March 2018 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43517
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 January 2021.