Exophyllum Weber-van Bosse, 1911
Holotype species: Exophyllum wentii Weber Bosse
Original publication and holotype designation: Weber-van Bosse, A. (1911). Notice sur quelques genres nouveaux d'algues de l'Archipel Malaisien. Annales du Jardin Botanique de Buitenzorg 24: 25-33.
Request PDFDescription: Thallus decumbent, flattened, cartilaginous, with irregularly foliose blades that attach to the substratum by short pedicels; subsequent blades arising from the upper surface of older blades. Immature thalli reniform with dentate margins, becoming mostly smooth and irregular in shape. Ventral surface uniform; dorsal surface mottled with numerous rounded protuberances that can extend into long haptera and develop as new blades. Trichoblasts absent. Structure uniaxial; each axial cell with 4 pericentral cells; central axis soon obscured by secondary cortication, when mature with a pseudoparenchymatous medulla of large hyaline cells, grading into a cortex of smaller pigmented cells. Secondary pit connections abundant between stellate inner cortical cells. Spermatangia in discoid or oval plates on the thallus surface. Procarps borne in the upper cortex of fertile thalli, with an auxiliary cell derived from a fertile axial cell, a supporting cell with lateral sterile groups, and a 4-celled carpogonial branch. After presumed fertilisation, the auxiliary and nearby sterile cells uniting to form a basal fusion cell bearing richly branched gonimoblast initials. Cystocarps sessile, globose, with a small ostiole, developing irregularly on the dorsal surface of the thallus. Mature cystocarp with a thick pericarp. Sterile traversing gonimoblast filaments present in the cystocarp cavity. Carposporophyte with a basal erect fusion cell supporting chains of branched gonimoblast filaments, these with terminal carposporangia. Tetrasporangia in curved club-like stichidia on the thallus surface, each with up to 9 pairs of sporangia to 200 ?m diam. in planar rows. Sporangia and polysiphonous stichidia pedicels completely covered by non-specialised cortical cells. Life history triphasic, with an isomorphic gametophyte and tetrasporophyte.
Information contributed by: Huisman (2018). The most recent alteration to this page was made on 2018-10-09 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.
Comments: Original collections from Indonesia; subsequently found in southern Japan (Tanaka 1950), the Philippines (Velasquez et al. 1975) and the Hawaiian Islands (Hollenberg 1968). Hollenberg (1968) described a male plant which convinced him that this genus, formerly referred to the Rhodymeniaceae, or regarded as of uncertain placement taxonomically, should be allied with the Rhodomelaceae despite the absence of a distinct polysiphonous thallus; this familial placement was later confirmed by Indy, N'Yeurt & Yasui (2006).
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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=40639
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 09 October 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 26 November 2024
