Belongs within: Fragilariaceae.
Synedra is a genus of elongate, linear diatoms (Crosby & Ferguson Wood 1959).
Characters (Crosby & Ferguson Wood 1959): Cells stipitate, single or adnate in small clusters, becoming free, or rarely not stipitate, in bundles; frustules elongate in valve view, linear or linear lanceolate; longitudinal median line well defined, pseudoraphe distinct; raphe absent; surface striate, punctate; plastids vary; pyrenoids may be present.
Synedra Ehrenberg 1830G75
|--S. acicularisG64
|--S. acus Kützing 1844W61a
| |--S. a. var. acusM70
| `--S. a. var. angustissima Grunow 1881M70
|--S. acuta Ehrenberg 1839CFW59
|--S. baculusG64
|--S. capitataG64
|--S. closteroidesCFW59
| |--S. c. var. closteroidesCFW59
| `--S. c. var. jaehrnefelti Mölder 1939CFW59
|--S. crystallina (Agh.) Kützing 1844CFW59
|--S. deformisG64
|--S. delicatissimaG64
|--S. dubia [incl. S. oxyrhynchus]G64
|--S. flexuosa [incl. S. biceps]G64
|--S. frauenfeldii Grun. 1863CFW59
|--S. fulgens (Grev.) Smith 1953G63 (see below for synonymy)
|--S. gaillonii (Bory) Ehrenberg 1838 [=Navicula gailloni Bory 1822]CFW59
| |--S. g. var. gallioniiG64
| `--S. g. var. minorG64
|--S. gibbosaG64
|--S. goulardii Brebisson ex Grun. in Cleve & Grun. 1880W61a
|--S. gracilisG64
|--S. grandisM01
|--S. hamataG64
|--S. hennedyana Greg. 1857W61a
|--S. investiensM01
|--S. kamtschaticaM01
|--S. longissimaG64
|--S. lunarisG64
|--S. minutaM01
|--S. minutissimaG64
|--S. pelagica Hendey 1937 [incl. S. spathulata Schimper in Karst. 1905 non O’Meara 1875]CFW59
|--S. pulchella (Ralfs) Kützing 1944CFW59
|--S. rumpensTJ06
| |--S. r. var. rumpensTJ06
| `--S. r. var. scoticaTJ06
|--S. salina W. Sm. 1853CFW59
|--S. splendens Kützing 1844CFW59 [incl. S. radiansG64]
|--S. superba Kützing 1844CFW59
|--S. tabulata (Ag.) Kützing 1844W61a (see below for synonymy)
| |--S. t. var. tabulataG75
| |--S. t. var. fasciculataG75
| |--S. t. var. obtusaG63
| `--S. ‘affinis’ var. parvaM01
|--S. teneraG64
|--S. truncataG64
|--S. ulna (Nitzsch) Ehrenberg 1838 [=Bacillaria ulna Nitzsch 1817]CFW59
| |--S. u. var. ulnaRA05
| |--S. u. var. acuminataG64
| `--S. u. var. danicaRA05
|--S. undulata (Bail.) Greg. 1857 [=Toxarium undulatum Bail. 1854]CFW59
|--S. vaucheriae Kützing 1844W61b
`--S. vertebraG64
Synedra fulgens (Grev.) Smith 1953G63 [=Exilaria fulgens Grev. 1827CFW59, Ardissonia fulgens (Grev.) Grun. in Cleve & Grun. 1880CFW59, Licmophora fulgens Kützing 1844CFW59]
Synedra tabulata (Ag.) Kützing 1844W61a [=Diatoma tabulatum Ag. 1832W61a; incl. Echinella acutaC99, Navicula acutaC99, Synedra affinis Kg. 1844W61a]
*Type species of generic name indicated
References
[C99] Cox, E. J. 1999. Studies on the diatom genus Navicula Bory. VIII. Variation in valve morphology in relation to the generic diagnosis based on Navicula tripunctata (O. F. Müller) Bory. Diatom Research 14 (2): 207–237.
[CFW59] Crosby, L. H., & E. J. Ferguson Wood. 1959. Studies on Australian and New Zealand diatoms. II.—Normally epontic and benthic genera. Transactions of the Royal Society of New Zealand 86 (1): 1–58, pls 1–9.
[G63] Giffen, M. H. 1963. Contributions to the diatom flora of South Africa. I. Diatoms of the estuaries of the eastern Cape Province. Hydrobiologia 21: 201–265.
[G75] Giffen, M. H. 1975. An account of the littoral diatoms from Langebaan, Saldanha Bay, Cape Province, South Africa. Botanica Marina 18: 71–95.
[G64] Gray, J. E. 1864. Handbook of British Water-weeds or Algae. R. Hardwicke: London.
[M70] Meel, L. van. 1970. Etudes limnologiques en Belgique. VI.–Les méandres de la Durme à Hamme (Province de Flandre Orientale). Bulletin de l’Institut Royal des Sciences Naturelles de Belgique 46 (13): 1–56.
[M01] Mereschkowsky, C. 1901. A list of Californian diatoms (concluded). Annals and Magazine of Natural History, series 7, 7: 505–520, pls 4–5.
[RA05] Rath, J., & S. P. Adhikary. 2005. A check list of algae from Chilika Lake, Orissa. Bulletin of the Botanical Survey of India 47: 101–114.
[TJ06] Taukulis, F. E., & J. John. 2006. Diatoms as ecological indicators in lakes and streams of varying salinity from the wheatbelt region of Western Australia. Journal of the Royal Society of Western Australia 89 (1): 17–25.
[W61a] Wood, E. J. F. 1961a. Studies on Australian and New Zealand diatoms. IV.—Descriptions of further sedentary species. Transactions of the Royal Society of New Zealand 88 (4): 669–698.
[W61b] Wood, E. J. F. 1961b. Studies on Australian and New Zealand diatoms. V.—The Rawson Collection of recent diatoms. Transactions of the Royal Society of New Zealand 88 (4): 699–712.