{{Short description|Genus of algae}} {{Automatic taxobox | image= Pyrobotrys rostratus as Spondylomorum quaternarium var. rostratum in Playfair 1918.jpg | image_caption = ''Pyrobotrys rostratus'' | taxon = Pyrobotrys | authority = Arnoldi, 1916<ref>Ein neuer Organismus aus der Volvocaceenordnung Pyrobotrys incurva. W Arnoldi, Jubiläumsband zu Ehren Timiriazeffs Moskau, S, 1916</ref> | type_species = Pyrobotrys incurvus | type_species_authority = Arnoldi<ref name=AlgaeBase>{{AlgaeBase genus | id=43496 | title=''Pyrobotrys'' Arnoldi, 1916 | access-date=2025-04-02 }}</ref> | subdivision_ranks = Species | subdivision = * ''Pyrobotrys acuminata'' Y.S.R.K.Sarma & R.Shyam * ''Pyrobotrys asiatica'' (Skvortzov) G.E.Huber-Pestalozzi * ''Pyrobotrys casinoensis'' (Playfair) P.C.Silva ** ''Pyrobotrys casinoensis var. elongata'' Korshikov & Anakhin ** ''Pyrobotrys casinoensis var. intermedia'' Y.S.R.K.Sarma & R.Shyam * ''Pyrobotrys desikacharyi'' Y.S.R.K.Sarma & R.Shyam * ''Pyrobotrys elegans'' (J.Behlau) H.Nozaki * ''Pyrobotrys elongata'' Korshikov * ''Pyrobotrys gracilis'' (Korshikov) Korshikov * ''Pyrobotrys incurva'' W.M.Arnoldi - type * ''Pyrobotrys korschikovii'' (L.A.Schkorbatov) Korshikov * ''Pyrobotrys minima'' H.Ettl * ''Pyrobotrys rostrata'' (G.I.Playfair) G.E.Huber-Pestalozzi * ''Pyrobotrys squarrosa'' (Korshikov) Korshikov * ''Pyrobotrys stellata'' (Korshikov) Korshikov }}
'''''Pyrobotrys''''' is a genus of green algae in the family Spondylomoraceae.<ref>See the NCBI [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=3063 webpage on Pyrobotrys]. Data extracted from the {{cite web | url=https://ftp.ncbi.nih.gov/pub/taxonomy/ | title=NCBI taxonomy resources | publisher=National Center for Biotechnology Information | access-date=2007-03-19}}</ref> It has a cosmopolitan distribution, found in fresh water rich in organic matter.<ref name=AlgaeBase/>
''Pyrobotrys'' consists of colonies (termed coenobia) of four, eight or 16 arranged in two or four tiers, with a star- or mulberry-like shape. Cells are spherical, ovoid, ellipsoid, or pear-shaped. Each has two equal flagella, two contractile vacuoles at the base of the flagella, and a large cup-shaped chloroplast with or without a stigma with no pyrenoids.<ref name=AlgaeBase/>
''Pyrobotrys'' reproduces both asexually and sexually. In asexual reproduction, each cell of the colony divides to form a daughter colony. In sexual reproduction, cells divide into 4, 8, 16, or 32 biflagellate isogametes, which fuse to form planozygotes, with four flagella. Upon germination, the planozygotes divide into four "gone cells" which then develop into new colonies.<ref name=AlgaeBase/>
Species of ''Pyrobotrys'' are distinguished based on the shape of the cells, number of cells in a colony, presence or absence of a stigma, and shape of the planozygote.<ref>{{cite journal|doi= 10.2216/i0031-8884-25-4-455.1|title= A taxonomic study of Pyrobotrys (Volvocales, Chlorophyta) in anaerobic pure culture|date= 1986|last1= Nozaki|first1= Hisayoshi|journal= Phycologia|volume= 25|issue= 4|pages= 455–468|bibcode= 1986Phyco..25..455N}}</ref>
==References== {{Reflist|1}}
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Category:Chlamydomonadales genera Category:Chlamydomonadales
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