Stomatochroon Palm, 1934: 15
Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridaeplantae
Phylum Chlorophyta
Class Ulvophyceae
Order Trentepohliales
Family Trentepohliaceae
Holotype species: Stomatochroon lagerheimii Palm
Taxonomic status: currently recognized as a distinct genus.
Description: Endophytic in plant leaves, often present on ventral side near drip tip. Externally visible thallus a single enlarged "central cell" comparable to pyriform head cell in Cephaleuros) emerging from host stomate. Central cell with few sterile trichomes and sporangiophores, each with one or more abscising zoosporangia. Within stomatal chamber, central cell connected to enlarged, lobed basal cell from which branches grow through intercellular spaces and produce additional plantlets at other stomates. Chloroplast parietal without pyrenoids. Nuclei in vegetative cells generally single, but occasionally double in young cells. Although ultrastructural studies limited, many morphological features, including abscising zoosporangia, similar to related genera. Cross walls likely contain plasmodesmata and zoosporangium-pedicel cross wall probably specialized. Asexual reproduction by zoospores with 8-16 spores in each sporangium. Zoospores and gametes typical of Trentepohliales (see Cephaleuros). Sexual reproduction isogamous and typical of order (see Cephaleuros) with biflagellate gametes released through pore-papillae as in other genera. Endophytic in plant leaves, often present on ventral side near drip tip. Externally visible thallus a single enlarged "central cell" comparable to pyriform head cell in Cephaleuros) emerging from host stomate. Central cell with few sterile trichomes and sporangiophores, each with one or more abscising zoosporangia. Within stomatal chamber, central cell connected to enlarged, lobed basal cell from which branches grow through intercellular spaces and produce additional plantlets at other stomates. Chloroplast parietal without pyrenoids. Nuclei in vegetative cells generally single, but occasionally double in young cells. Although ultrastructural studies limited, many morphological features, including abscising zoosporangia, similar to related genera. Cross walls likely contain plasmodesmata and zoosporangium-pedicel cross wall probably specialized. Asexual reproduction by zoospores with 8-16 spores in each sporangium. Zoospores and gametes typical of Trentepohliales (see Cephaleuros). Sexual reproduction isogamous and typical of order (see Cephaleuros) with biflagellate gametes released through pore-papillae as in other genera.
Comments: Widespread in tropical and subtropical regions. Three additional species described by Thompson but never published. As in other Trentepohliales, Stomatochroon accumulates cytoplasmic carotenoids and is orange-red. When abundant it blocks enough stomates to damage host leaf.
NCBI Nucleotide Sequences
No sequences have been found on the NCBI site.
Numbers of names and species: There are 7 species (and infraspecific) names in the database at present, of which 4 have been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently 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):
Stomatochroon coalitum R.H.Thompson & D.E.Wujek P
Stomatochroon coalitus Thompson & Wujek C
Stomatochroon consociatum R.H.Thompson & D.E.Wujek P
Stomatochroon consociatus Thompson & Wujek C
Stomatochroon lagerheimii Palm C - type
Stomatochroon reniforme R.H.Thompson P
Stomatochroon reniformis Thompson & Wujek C
Information contributed by: R. L. Chapman. The most recent alteration to this page was made on 10 Dec 2004 by Fabio Rindi.
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.
