Graesiella T.Kalina & M.Puncochárová, 1987

Holotype species: Graesiella vacuolata (Shihira & Krauss) Kalina & Puncochárová

Original publication and holotype designation: Kalina, T. & Puncochárová, M. (1987). Taxonomy of the subfamily Scotiellocystoideae Fott 1976 (Chlorellaceae, Chlorophyceae). Algological Studies 45: 473-521.

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Description: Unicellular thalli comprised of broadly ellipsoidal or globose cells 5-15 x 3-14 µm. Cell wall appearing smooth, ultrastructurally with fine network of ribbing; cell wall with inner mostly polysaccharide layer and outer trilamellate layer formed by coalescence of trimellar plates. Protoplast with numerous, occasionally granular vacuoles. Cells uninucleate with centrioles; chloroplast single and parietal, divided into segments only one of which contains a pyrenoid with starch envelope. Asexual reproduction by autospores, 2-8(-16) per sporangium; released by rupture of parental cell wall. In culture, autospore release inhibited by high concentrations of CO2. Flagellated stages and sexual reproduction unknown. Graesiella studied in culture; isolated from tree bark in Philadelphia. Genus placed in subfamily Scotiellocystoideae and distinguished from Chlorella based on cell wall structure and development and presence of acetoresistant material and centrioles. Chemotaxonomy of pigments and 18S rRNA sequence analysis supports separation of genus from Chlorella and affinities with Scenedesmaceae rather than Chlorellaceae. Unicellular thalli comprised of broadly ellipsoidal or globose cells 5-15 x 3-14 µm. Cell wall appearing smooth, ultrastructurally with fine network of ribbing; cell wall with inner mostly polysaccharide layer and outer trilamellate layer formed by coalescence of trimellar plates. Protoplast with numerous, occasionally granular vacuoles. Cells uninucleate with centrioles; chloroplast single and parietal, divided into segments only one of which contains a pyrenoid with starch envelope. Asexual reproduction by autospores, 2-8(-16) per sporangium; released by rupture of parental cell wall. In culture, autospore release inhibited by high concentrations of CO2. Flagellated stages and sexual reproduction unknown. Graesiella studied in culture; isolated from tree bark in Philadelphia. Genus placed in subfamily Scotiellocystoideae and distinguished from Chlorella based on cell wall structure and development and presence of acetoresistant material and centrioles. Chemotaxonomy of pigments and 18S rRNA sequence analysis supports separation of genus from Chlorella and affinities with Scenedesmaceae rather than Chlorellaceae.

Information contributed by: T. Kalina & D. Garbary. The most recent alteration to this page was made on 2017-05-02 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

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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=45584

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 02 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 02 March 2024

 
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