Eudesme J.Agardh, 1882
Lectotype species: Eudesme virescens (Carmichael ex Berkeley) J.Agardh
Original publication: Agardh, J.G. (1882). Till algernes systematik. Nya bidrag. (Andra afdelningen.). Lunds Universitets Års-Skrift, Afdelningen for Mathematik och Naturvetenskap 17(4): 1-134, 3 plates.
Request PDFType designated in: De Toni, G.B. (1891). Sylloge algarum omnium hucusque cognitarum. Vol. II. Sylloge Bacillariearum. Sectio I. Rhaphideae. pp. [i-iii]. [i]-cxxxii, 1-490. Patavii [Padua]: Sumptibus auctoris.
Description: Plants epilithic in intertidal to upper subtidal zone, solitary or loosely caespitose, up to 30 cm in height, 1-2 times branched, soft, gelatinous, haplostichous, solid, attached on the substrata by small discoidal rhizoidal holdfast. Erect thallus composed of multiaxial medullary filaments, giving rise to lateral colorless branched filaments bearing pigmented assimilatory filaments. Medullary filaments very loosely bound together, composed of colorless large cells 40-70 _m in diameter, 1.5-2.5 times as long as the diameter, constricted at the cross walls. Assimilatory filaments slender, branched, isodiametric, cylindrical below, becoming slightly swollen above, as long as 15-20 cells, sometimes with short branchlets near terminal part. Each cell contains several disc-shaped chloroplasts with pyrenoid. Phaeophycean hairs present. Unilocular sporangia form from basal part of assimilatory filaments, irregular in shape, sessile, 80-120 _m ( 50-75 _m in size. Plurilocular sporangia not detected on erect thalli. In Japanese E. virescens, asexual direct type of life history is reported (Kawai 1986). Unispores 7-7.5 _m x 4.5-5 _m in size, normally biflagellated, pear-shaped containing a single chloroplast with stigma, negatively phototactic, germinate unipolarly without leaving emptied embryospore, develop into bushy microthalli which directly form multiaxial macrothallus bearing unilocular sporangia. There was no clear regulation of life history by temperature or photoperiod, although macrothalli developed better under long day conditions. On the other hand, Cole (1967) reported sexual reproductions in the microthalli derived from unispores, however, zygotes developed into microthalli again and did not form macrothalli. Cole reported chromosome counts of 2n=20 (sporophyte), n=10 (gametophyte) and Kawai (1986) reported n=10-12 through the life history. Plants epilithic in intertidal to upper subtidal zone, solitary or loosely caespitose, up to 30 cm in height, 1-2 times branched, soft, gelatinous, haplostichous, solid, attached on the substrata by small discoidal rhizoidal holdfast. Erect thallus composed of multiaxial medullary filaments, giving rise to lateral colorless branched filaments bearing pigmented assimilatory filaments. Medullary filaments very loosely bound together, composed of colorless large cells 40-70 _m in diameter, 1.5-2.5 times as long as the diameter, constricted at the cross walls. Assimilatory filaments slender, branched, isodiametric, cylindrical below, becoming slightly swollen above, as long as 15-20 cells, sometimes with short branchlets near terminal part. Each cell contains several disc-shaped chloroplasts with pyrenoid. Phaeophycean hairs present. Unilocular sporangia form from basal part of assimilatory filaments, irregular in shape, sessile, 80-120 _m ( 50-75 _m in size. Plurilocular sporangia not detected on erect thalli. In Japanese E. virescens, asexual direct type of life history is reported (Kawai 1986). Unispores 7-7.5 _m x 4.5-5 _m in size, normally biflagellated, pear-shaped containing a single chloroplast with stigma, negatively phototactic, germinate unipolarly without leaving emptied embryospore, develop into bushy microthalli which directly form multiaxial macrothallus bearing unilocular sporangia. There was no clear regulation of life history by temperature or photoperiod, although macrothalli developed better under long day conditions. On the other hand, Cole (1967) reported sexual reproductions in the microthalli derived from unispores, however, zygotes developed into microthalli again and did not form macrothalli. Cole reported chromosome counts of 2n=20 (sporophyte), n=10 (gametophyte) and Kawai (1986) reported n=10-12 through the life history.
Information contributed by: H. Kawai. The most recent alteration to this page was made on 2021-02-22 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 feminine.
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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=37342
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 22 February 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 20 April 2024
