''Fragilaria'' is a genus of

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

and saltwater

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s. It is usually a colonial diatom, forming filaments of cells mechanically joined by protrusions on the face and in the center of their valves. The individual diatoms appear swollen in their centers where they are joined to the colonial ribbon. The genus grows as both plankton and benthic species, free living in colonies or as

epiphytes An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

. Some species are bloom forming diatoms in eutrophic lakes. The type species is '' Fragilaria pectinalis'' Lyngbye from designating a

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes ...

from ''Conferva pectinalis'' O.F.Müller. The taxonomy of the genus is still uncertain. ''Fragilaria'' has been the dominant genus of diatoms in

Lake Mývatn A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

in Iceland for at least 1200 years. The genus currently accounts for around 93% of all diatoms in the lake.

Description

The ''Fragilaria'' have a pseudoraphe, rather than a true longitudinal groove in their valves. The valves are symmetrical with transverse striae.

Selected species

*'' F. acidoclinata'' *'' F. aconicinnum'' *'' F. acus'' *'' F. acutirhombica'' *'' F. acutiuscula'' *'' F. alpestris'' *'' F. amphicephaloides'' *'' F. annulata'' *'' F. aquaplus'' *'' F. arctica'' *'' F. austriaca'' *'' F. barbararum'' *'' F. barbatula'' *'' F. bidens'' *'' F. bipunctata'' *'' F. birostris'' *'' F. brevistriata'' *'' F. bronkei'' *'' F. californica'' *'' F. canariensis'' *'' F. cassubica'' *'' F. constricta'' *'' F. construens'' *'' F. crassirhombica'' *'' F. crotonensis'' *'' F. demerarae'' *'' F. denticulata'' *'' F. dibolos'' *'' F. dzonoticola'' *'' F. ehrenbergii'' *'' F. eichornii'' *'' F. excissa'' *'' F. famelica'' *'' F. flexura'' *'' F. foliolum'' *'' F. fragilarioides'' *'' F. fremontii'' *'' F. gedanensis'' *'' F. germanii'' *'' F. glebula'' *'' F. gnathastoma'' *'' F. goulardii'' *'' F. gracilis'' *'' F. gracillicima'' *'' F. gracillima'' *'' F. grandis'' *'' F. grunowii'' *'' F. hantzschiana'' *'' F. henryi'' *'' F. hirosakiensis'' *'' F. hoelii'' *'' F. husvikensis'' *'' F. hyalina'' *'' F. improbula'' *'' F. incisa'' *'' F. incognita'' *'' F. interstincta'' *'' F. islandica'' *'' F. kriegeriana'' *'' F. labei'' *'' F. lacus-baikalensis'' *'' F. lacus-baikali'' *'' F. lenzii'' *'' F. leptarthra'' *'' F. longiceps'' *'' F. longifusiformis'' *'' F. magocsyi'' *'' F. marina'' *'' F. mazamaensis'' *'' F. micra'' *'' F. microvaucheriae'' *'' F. miniscula'' *'' F. nanana'' *'' F. nanoides'' *'' F. nevadensis'' *'' F. northumbrica'' *'' F. oblongata'' *'' F. opacolineata'' *'' F. pacifica'' *'' F. pantocsekii'' *'' F. paradoxa'' *'' F. pararumpens'' *'' F. parva'' *'' F. patagonica'' *'' F. pelta'' *'' F. pennsylvanica'' *'' F. perdelicatissima'' *'' F. perminuta'' *'' F. pseudoconstruens'' *'' F. pseudolaevissima'' *'' F. ptagonica'' *'' F. punctata'' *'' F. punctiformis'' *'' F. quebecensis'' *'' F. radians'' *'' F. recapitellata'' *'' F. rhodana'' *'' F. riesgoviensis'' *'' F. robusta'' *'' F. rolandschmidtii'' *'' F. rostrata'' *'' F. rotundissima'' *'' F. sandellii'' *'' F. santaremensis'' *'' F. saxoplanctonica'' *'' F. schulzi'' *'' F. schulzii'' *'' F. similis'' *'' F. sinuata'' *'' F. smithiana'' *'' F. socia'' *'' F. sopotensis'' *'' F. spinarum'' *'' F. striatula'' *'' F. submicroscopica'' *'' F. suboldenburgiana'' *'' F. tenera'' *'' F. tenuicollis'' *'' F. toxoneides'' *'' F. turgens'' *'' F. uliginosa'' *'' F. ulna'' *'' F. ulnus'' *'' F. utermoehlii'' *'' F. vaucheriae'' *'' F. viereckiana'' *'' F. virescens'' *'' F. vitrea'' *'' F. zeilleri''

References

External links

* {{Taxonbar, from=Q1440428 Diatom genera Fragilariophyceae