revision of the genus fragilaria | ResearchGate

This article was downloaded by: [Natural History Museum], [Dr David M. Williams] On: 01 November 2011, At: 01:44 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Diatom Research Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tdia20

REVISION OF THE GENUS FRAGILARIA a

David M. Williams & Frank E. Round

b

a

Department of Botany, British Museum (Natural History), Cromwell Road, London, SW7 5BD, England b

Department of Botany, University of Bristol, Bristol, BS8 1UG, U.K.

Available online: 31 Oct 2011

To cite this article: David M. Williams & Frank E. Round (1987): REVISION OF THE GENUS FRAGILARIA , Diatom Research, 2:2, 267-288 To link to this article: http://dx.doi.org/10.1080/0269249X.1987.9705004

PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

Diatom Research (1987) Volume 2 (2), 267-288.

REVISION OF THE GENUS FRAGILARM Downloaded by [Natural History Museum], [Dr David M. Williams] at 01:44 01 November 2011

David M. Williams Department of Botany, British Museum (Natural History), Cromwell Road, London SW7 SBD, England

Frank E. Round Department of Botany, University of Bristol, Bristol BS8 lUG, U . K . A large number of species usually placed in Fragilaria have been examined, mainly by scanning electron microscopy. As a result Fragilaria is more narrowly circumscribed, with F.capucina as the type species. Six species are definitely placed in Fragilaria and others noted for further investigation. Five genera are separated from Fragilaria;these are Staurosira (to encompass the ‘construm’ group), Staurosirella (type species S .lapponica = F .lapponica), Pseudostaurosira (type species S. brevistriata = F .brevistriata), Punctastriata (type species P .linearis)and Neofiagilaria (type species N.virescens = F.virescens). Some species other than the type have also been transferred to the new genera and others indicated as requiring further study. The characters used for their distinction are discussed, and include valve striation, linking spines, apical pore fields, rimoportulae, girdle and plastids.

INTRODUCTION Fragihria Lyngb. was originally conceived for species that form linear colonies in which each individual frustule is attached to another rather than to a particular substratum (Lyngbye 1819). Early workers recognized a range of araphid genera with ribbon-like colonies which were later rejected in favour of a composite taxon under the name Fragihria. Generic circumscriptions of araphid diatoms originally used characters of the valve, colony and plastids, but later it appears that workers concentrated on valve characters, relying almost entirely on cleaned material. Hustedt’s compilation (1927-66 published in 1931) is a good example of this later approach. In both his great works (the 1927-66Rabenhorst Kryptogamen Flm-a and the 1930Siisswasser Flm-a)Hustedt discussed the problems of distinguishing isolated Fragihria valves from those of Synedra but he clearly considered that Fragihria formed linear colonies (he was at pains to explain how to treat material to see this) and that Synedra could, whilst growing rapidly, form short chains of cells - as can many diatom genera. He discussed the possible combination of Fragihria and Synedra but rejected it on the grounds that it would necessitate combination of other genera and would be unhelpful - it is useful to quote here his actual words: ..‘Ihre Kombinarion wiirde auch die Zusammenfassung der vielen kleinen Gattungen nach sich ziehen, eine entstehende Gesamtgattung wiirde wenig iibersichtlich sein, ohne dass damit der Sache gedient ware!’ Patrick 8z Reimer (1966) and Schoeman (1974) commented that the two genera may not be distinct and Lange-Bertalot (1980) combined all the common freshwater species of Synedra with Fragilaria, despite the wide range of variation in Synedra that was demonstrated by Round (1979). Poulin et al. (1984, 1986), in a survey of a number of species of both Fragilaria and Synedra, concurred with Lange-Bertalot, but suggested subgeneric division based on colonial and other ultrastructural features. Our recent investigations have shown that while colony formation is not in itself sufficient to justify separation of genera, there are often differences in many other characters which can be used to support the subdivision of genera such as Synedra (Round 1984, Williams

Downloaded by [Natural History Museum], [Dr David M. Williams] at 01:44 01 November 2011

268

D. M. WILLIAMS AND F. E. ROUND

1986, Williams & Round 1986) and Frugilariu. In fact, however, the paper of Lange-Bertalot (1980) did not deal in any detail with the species which we here propose should be removed from Frugilariu; others that he dealt with we have already discussed (Williams & Round 1986) either as Synedru or new genera. In this paper we have approached the genus Fragiluria in the same way as we did Synedru. Examination of a wide variety of morphological features has revealed several new definable genera, along with re-definitions of Frugiluriu and Stuurosiru Ehrenb. This paper is by no means a definitive account of all the taxa ascribed to Frugiluriu - it is merely a beginning of what needs to be a very lengthy study of a very heterogenous group of genera.

MATERIAL AND METHODS The material examined in this study is mostly preserved in the British Museum (Natural History) (BM) or was collected by F.E.R. Scanning electron microscopy (SEM) was performed on a Hitachi S800 field emission microscope (BM) or a Philips 501 (Botany Department, Bristol University). The terminology used in this paper is principally that of Ross et al. (1979), with a few additions from recent proposals. The term sternum has been used for a centrally thickened axial area (Round 1979) and ocellulimbus for the inset apical pore-field (Williams 1986).

OBSERVATIONS Fragilaria Lyngbye 1819: 182. Frustules rectangular in girdle view, usually forming linear colonies (Figs 1,2); some species have been reported as growing singly. Valves linear to elliptical; apices rostrate to capitate (Figs 4, 7-10). Striae more or less evenly spaced; areolae regularly spaced (Figs 4-11) with delicate external vela often strutted and discoid, i.e. they are almost certainly a type of rota (Fig.5). At the valve centre the striae are often occluded, appearing as ghost structures (Fig. 1); in some species the valve face/mantle junction is without areolae. Sternum narrow. Apical pore fields present, situated at the apices of the mantle; the pore fields are of the ocellulimbus type, but they are weakly developed (Figs 12,13). A single rimoportula is present, usually lying at a pole (Fig.13). Spines present, occasionally interrupting the rows of areolae at the junction of valve face and mantle and in some species occurring around the valve apices (Figs 3,4,14). Cingulum of a few simple, open, ligulate copulae (Figs 3,14). Valvocopula extensions of the pars interior fit onto valve costae; a single row of poroids is present on the pars interior. Two longitudinally aligned plastids lying principally against the valves. Type species: F.capucinu Desmaz.’ Species of Frugdariu form linear colonies, with frustules attached by adjacent inter-digitating spines. We have restricted the definition of Frugiluriu to those species that have simple striae, a 1 There is some doubt concerning the application of the generic name Frugiluriu Lyngb. The type species of the genus is F.pectinalis (0.F.Mull.) Lyngb. which is apparently synonymous with F.cupucina but this has not been established with certainty (Patrick & Reimer 1966). However, over the past 60 years the genus has been understood to be typified by F.-’nu and we have followed that usage. The consequence is that it may be necessary to conserve the genus based on this type.The marine species Frugiluria striatulu (see Hasle & Syvertsen 1981)does not belong to Frugiluriu s m Williams & Round and, if the above synonymy is not established, should take the generic name. If conservation is upheld Frugiluriu s o i z t d a will need a new generic name.


REVISION OF THE GENUS FIUGILARIA

269

few open girdle bands, and a simple type of ocellulimbus at each pole. We include some species that have previously been classified in Synedru and some of the species that Lange-Bertalot (1980) considered as ‘paired’, in the sense of living either as colonies of cells or as individual cells. Frq‘hriu cupucinu Desmazieres 1825: Fasc. 10,no. 453. Synonyms: Synedru rumpens Kutzing 1844:69,pl. 16/6,fig. 4-5.S.rumpens var. scotiu Grunow in Van Heurck 1880-85:pl. 40,fig. 11. Type locality: Not clear. [France]. Type slide: BM 81302. from BM herbarium material exiccata set. Type material of Synedru rumpens examined: Lectotype BM 18357 designated by LangeBertalot (1980), see p. 747, figs 39, 40. Valves linear to elliptical, parallel-sided at the centre but soon tapering towards slightly rounded to capitate poles (Figs 3-7). 5-85 p m in length and 5-10p m in breadth (measurements here and in subsequent descriptions according to Hustedt 1931 and Patrick & Reimer 1966).Striae uniseriate, usually evenly spaced, 12-18in 10 pm; delicate vela present in the areolae. Central area present, occasionally unilateral, and formed by occlusion of striae. The single rimoportula is orientated obliquely, or transapically; it is not necessarily aligned with a stria. Apical pore fields with approximately 8-10columns of pores, with approximately 4 pores per column. Spines are present at the junction of valve face and mantle: some are small stubs; others are more complex interlocking structures and these usually occur at the centre of the valve, adjacent to the central area. A series of irregularly spaced plaques occurs along the external rim of the mantle border. Cingulum of 3-4open, ligulate and undifferentiated copulae which are identical except for width; the pars interior of the valvocopula is undulate. A single row of poroids is situated at the pars interior-pars media junction of each copula. The ligulae of the copulae extend in both an advalvar and abvalvar direction. No poroids occur on the ligula. This genus also includes the following species that we have examined - there are undoubtedly others. Frugihriu vuucheriae (Kutz.) Petersen 1938: 167, fig. la-$ Basionym: Exilaria vuucherim Kiitzing 1833a: no. 24; 1833b: 560,fig. 38. Type locality: ‘Sie kam an Vuucheriachvutu in einer Quelle bei Weissenfels in grosser Menge vor, ausserdem fand ich sie auch noch an Scytosiphon velutinus im Hallischen, aber etwas kleiner und zarter.’ Type slide: BM 78023 (Also BM 18234). We consider this a distinctive species and not a variety of F.cupucinu as did Lange-Bertalot. Frag‘hriu mumaensis (Sovereign) Lange-Bertalot 1980:748. Basionym: Synedru mazumuensis Sovereign 1958: 111, pl. 2, figs 10-15(our Figs 8,ll). Type locality: U.S.A. Oregon, Crater Lake National Park, Emerald Pool. Type slide: CAS 3463 (Sov. 488-11,Sovereign, 1960.) Fragihriu miniscuh (Grun. in Van Heurck), Williams & Round, comb. mu. Basionym: Synedru miniscuh Grunow in Van Heurck (1880-5):pl. 39, fig. 13. Type locality: ‘Fossile a Franzenbad.’ Fragilariu radians (Kutz.) Williams & Round, cumb.nov. Basionym: Synedru radians Kiitzing 1844:64,pl. 14, fig. 7. Type locality: ‘An Chdophmu fructu bei Tennstadt!’ Type slide: BM 18192. Frugihriu teneru (W. Sm.) Lange-Bertalot 1980:946. Basionym: Synedru teneru W. Smith 1856: 98. Type locality: Saltcoats, New Forest, Lough Alloa, Co. Cork, Blarney. Type slide: BM 23803 Blarney, Co. Cork. (see Fig.9). Fragilaria crotunensis Kitton 1869: 110, t.fig. 81. Type locality: Croton Water supply, New York. Ty$e slide: BM 27963 ( see Crawford et ul., 1985 for a detailed account of this species at the SEM level). (Figs 1,2). Other Fragihriu species which we feel should be retained here but need further study are F. mqulis Heiberg, F . bidens Heiberg, F. frugihrioides(Grun. in Van Heurck) Cholnoky, F. intermedia (Grun.) Grunow in Van Heurck, Synedru incisu Boyer (=Prugihriu incisu (Boyer) Lange-Bertalot), and Synedru sociu Wallace (= Frugiluriu sociu (Wallace) Lange-Bertalot).



270

Figs 1-6. Fragihria. Fig.1. Colony of Fragihria m o t o m i s , LM. Bar = 10 pm. Fig.2. Colony of F.motomis, SEM. Bar = 10 p m . Fig.3. F.capucinu. Girdle view of cells in colony. Bar = 1.2 pm. Fig.4. F.capucina. Single cell. Bar = 10 pm. Fig.5. F.vauheriu. Bar = 2.0 pm. Fig.6. F.tenera. Bar = 0.75 pm.

271


REVISION OF THE GENUS FRAGZLARZA

Figs 7-14. Fragihria. Fig.7. F.capucina. Bar = 7.5 pm. Fig.8. F.mazumaensis. Bar = 4 pm. Fig.9. F . t e w a . Bar = 7 pm. Fig.10. F.vuuch&. Bar = 2.5 pm. Fig.11. F.mumaensis. Bar = 1 pm. Fig.12. Fragihriaspp. Twocellsshowing apical pore field, copulae and plaques on valve mantle. Bar = 0.5 pm. Fig.13. F.vaucheriae. Internal view showing the rimoportula. Bar = 1 pm. Fig.14. Fragilaria spp. Apices of cells in colony. Bar = 0.5 pm.

272



Staurosira Ehrenberg 1843: 45. Frustules rectangular in girdle view, frequently in chains (Figs 15,19,20). Valves elliptical (Figs 19,20) or so expanded centrally as to appear k cruciform (Figs 15-17). Valve surface ribbed; sternum narrow except at the centre. Striae uniseriate; the small cross-members evenly spaced. Areolae elliptical or linear; vela present. Apical pore-fields present but usually greatly reduced, consisting of between 4 to 15 pores (Figs 15,18). Spines interlocking and deflected outwards from the valve face; their tips often flattened or branched. The spines at the centre are sometimes simple and tapered and at the poles too they can be simple tubular structures. Each spine usually hollow, sited on the interstriae. Mantle plaques sometimes absent but often also hidden in complete frustules. No rimoportulae observed. Cingulum of 6-8 open, ligulate, plain, copulae often curved towards the poles (Figs 18-20). Valvocopula large, with extensions of the pars exterior onto the costae. The copulae are much narrower but are morphologically identical to each other and the valvocopula. Plastids: two large plates, situated adjacent to the valve girdle. Type species: Staurosira construens Ehrenberg. Ehrenberg described three species as belonging to Staurosira before giving a description of the genus. However, later when he described Staurosira, he referred only ‘construens’ to it, thus making it the generitype. Ehrenberg’s generic description was brief and dealt with the distinctive shape of Staurosira construens :‘Testula minima, laevis, angulis productis, duobus oppositis iongioribus tenuioribus.’ Later, Grunow (1862) distinguished a group of species that he took to be equivalent to Staurosira, characterising the genus mainly by the width of the central sternum: Staurosira has a wide sternum at the centre whilst Fragilaria is narrow at this area. He subdivided both into freshwater and marine components; this is certainly correct although what tma are involved, especially in the marine environment, has not been completely resolved. Petit (1877) kept Staurosira distinct from Fragilariu, indicating that many of the species, although similar in some morphological features, had a different plastid arrangement. When observed by LM, the group of species that we place in Staurosira are not easily distinguished from those of Staurosirella nov. gen., Pseudostaurosira nov. gen. ,Punctastriata nov. gen. or Opephma Petit (this genus is currently being re-assessed by FER); all lack rimoportulae and have a wide valvocopula. Staurosira is distinguished by the construction of the cingulum, the type of areolae, and the small size of the apical pore-field. The features of the genus are largely submicroscopic and hence we cannot be definite on the number of currently recognised species of Fragiluria that should be included. Equally, it is evident from published reports that some specimens identified as F . elliptica and F . c m t w n s should be placed in other genera. Staurosira construens Ehrenberg 1843a: 45. Synonyms: Odontidium tabelluria W. Smith 1856: 17, pl. 34, fig. 291. Fragilaria construens (Ehrenb.) Grunow 1862: 371. Type locality: ‘...Newhaven in Nord-Amerika.. .’ Frustules rectangular in girdle view; valves with central inflation, slightly cruciform, 7-25 p m in length, 5-12 p m in breadth (sizes as quoted in the literature, Hustedt 1931, Patrick & Reimer 1966). Valve surface ribbed, sternum narrow except at the centre. Striae uniseriate, 14-18 in 10 pm, with small evenly spaced cross-members. Areolae elliptical or linear, with simple cribra. Apical pore-fields present, consisting of 4-8 pores. Spines interlocking and deflected outwards from the valve face; tips slightly branched. Each spine interrupting an interstria; hollow. Mantle plaques absent. No rimoportulae observed. Cingulum of 6-8 open, ligulate, plain copulae. Copulae narrower than the valvocopula but morphologically identical. Plastids: two large plates, situated adjacent to the valve girdle (Figs 15-17). This genus should also include the following species: Staurosira elliptica (Schumann) Williams & Round, comb.nov. Basionym: Fragilaria elliptica Schumann 1867: 52, pl. 1, fig. 5 . Type locality: Not clear. Type slide: PH (examined from micrographs kindly supplied by Dr. K.E. Camburn).

273


REVISION OF THE GENUS FRAGILARIA

Figs 15-20. Staurosiru. Fig.15. Three cells of S.consmtens. Note the small apical pore field on the upper valve. Bar = 4 pm. Fig.16. S . c o n s m . Bar = 2 p m . Fig.17. S.construens,internal view. Bar = 4.3 pm. Fig.18. S.eZliptica(?).Bar = 3 pm. Fig. 19. S.eZZiptica. Bar = 3 pm. Fig.20. S.eZZiptica. Bar = 2.5 pm.

274



This species has been examined in detail by Haworth (1974). She points out that correct determination has often not been possible since other taxa are of similar appearance in the LM. Although Haworth’s study clarifies certain aspects of the morphology there are still many records of the species where further study is needed, particularly in the light of our generic distinctions. For instance micrographs in Archibald (1983) illustrate a particularly complex closing plate (especially pl. 27, fig. 520), suggesting his specimens can be distinguished from those outlined by Haworth (Figs 19.20). Stautosirella Williams & Round, gen.nm. Frustules rectangular (Fig.24), attached and in chains, either linked at the corners or by valve face to face contact (Fig.26). Valves elliptical to linear (Fig.21), occasionally cruciform (Fig.22). Striae uniseriate, with extensive cross-members delimiting linear areolae which contain finely branched closing plates. Sternum wide. Apical pore-fields usually large (Fig.25), extending onto the valve face and mantle; sometimes absent. Spines situated on the valve face edge between areolae; each spine bifurcate or more diffusely branched (Fig.26). Mantle plaques usually present. Cingulum of 8-10 open, plain, ligulate copulae (Fig.24). Valvocopula large; copulae delicate with granules along the abvalvar edge. Plastids: two large parietal plates lying adjacent to the girdle. Frustulum cingulari aspectu rectangulare. Valvarum elliptica circumscriptio vel lineari vel media vel cruciformi. Striis uniseriatis. Sternum latus. Chromatophora duo. Type species. Frugiluriu lupponica Grun. in Van Heurck. This genus differs from Stuurosiru by the nature of the cross-members of the striae, the type of spine structure and the granular appearance of the abvalvar portion of the individual copulae. Stuurosirellu lapponicu (Grun. in Van Heurck) Williams & Round, comb.nov. Basionym: Frugiluriu lupponica Grunow in Van Heurck 1880-5: pl. 45, fig. 35. Type locality: Not given. Type slide: ‘...one slide from Finnish Lappland (Grunow Herbar. Praparat no. 1477) with which the name lapponicu would appear to be connected.’ (Haworth 1974, p. 74-75 see her fig. 1, which is a micrograph of Grun. no. 1477). Frustules rectangular, attached in chains by valve face to face contact (Figs 21,26,27). Valves linear, 4-6 p m in width, 12-40 p m in length. Striae uniseriate, 6-9 in 10 pm, with extensive crossmembers and delicate closing plates. Sternum wide. Apical pore-fields reduced or absent. Spines situated on the valve face edge, each spine dichotomously branched. Mantle plaques usually present, small. Cingulum of 8-10 open, plain, ligulate copulae. Valvocopula large; copulae delicate with granules along the abvalvar edge. Plastids: two large parietal plates lying adjacent to the girdle. Also included in this genus are: Stuurosirellu pinnuta (Ehrenb.) Williams & Round, comb.nov. Basionym: F r u g i l u ~pinnutu Ehrenberg 1843b: 415, pl. 3 (6), fig. 8 a-e. Type locality: ‘Moctezuma Fluss’ (Ehrenberg 1843b: 376). ‘San Pedro y San Pablo Mexico, Moctezuma F1. , Mexico, Richmond Virginien, New York?, Newhaven Bridgewater, Spencer Mass., Island.’ (Ehrenberg 1843: 415, pl. 3 (6), fig. 8 a-e; erroneously indicated pl. 1 (3), 9, as a specimen which is F . striatulu). This species has been examined in detail by Haworth (1974). Her SEM’s show very clearly paired spines. However, it is difficult to be precise about the structure of the girdle from her SEM’s. It appears to have two copulae that are much narrower than the valvocopula (1974, p. 77, fig. 7). The TEM in Podzorski (1985) is an entirely different species. His specimen has a distinctive porefield at each pole and simple, large areolae. This should probably be placed within Pseudostuurosiru.

Figs 21-27. Staurosirella. Fig.21. S.lapponica. Bar = 0.75 pm. Fig.22. S.leptostauron. Bar = 6.5 pm. Fig.23. S.leptostauron. Valve apex showing the large apical pore field. Bar = 2 pm. Fig.24. S.aficana. Showing numerous copulae and plaques on the valve mantle. Bar = 2.5 pm. Fig.25. S.aficana. Valve apex showing the characteristic apical pore field. Bar = 0.85 pm. Fig.26. S.lapponica. Complex linking spines. Bar = 0.65 pm. Fig.27. S.lapponica. Bar = 0.55 pm.



275


276 D. M. WILLIAMS AND F. E. ROUND Staurosirella africana (Hust.) Williams & Round, comb.nov. Basionym: Fragilaria africana Hustedt 1949:62, pl. 2, figs 29-34. Type locality: ‘Vereinzelt im Eduardsee im Oberflachenplankton bei Bugazia.. .Tanganikasee.. .’ Staurosirella leptostauron (Ehrenb.) Williams & Round, comb.nov. (Figs 22,23). Basionym: Biblarium leptostauron Ehrenberg 1854:pl. 12, figs 35, 36. Synonyms: Staurosira pinnata Ehrenberg 1854: pl. 5(2), fig. 24; Odontidium ? harrisonii W. Smith 1856: 18, pl. 60, fig. 373; Fragilaria harrisonii (W. Sm.) Grunow 1862: 368; Fragilaria leptostauron (Ehrenb.) Hustedt 1931 (in 1927-66):153, fig. 668 a-b. Type locality: ‘Torf von Newhaven, Connecticut, Nord-Amerika, T.V. ii, F. 24.’ Pseudostaurosira Williams & Round, gen.nov Frustules rectangular, forming chains (Figs 32,34-36).Valves elliptical to linear (Figs 32-36), often undulate, occasionally cruciform (Figs 28-31). Striae uniseriate consisting of a few large elliptical areolae and often smaller round areolae rarely more than four areolae per stria. Closing plate delicate and highly branched. Sternum wide. Apical pore-fields not always present; if present usually consisting of a few pores (Fig.37). Rimoportulae absent. Mantle plaques present along the mantle edge (Figs 28,37). Spines situated along the valve edge usually in a somewhat plain region of the valve, sometimes branched at the tips. Cingulum of several open, plain, ligulate copulae. Valvocopula large, non-areolate. Plastids not known. Frustulum cingulari aspectu rectangulare ,catenas formant. Striis uniseriatis quaque areolatio ovatus. Cingulum ex quatuor redimiculus incompletis ligulatis constanti. Valvocopula et haud areolatae. Type: Fragilaria brevistriata Grunow in Van Heurck This genus differs from Staurosira by the nature of the striae, the shape of the central area and the small size of the pore-fields. It is difficult to estimate the number of species that should be included in this genus without detailed ultrastructural examination of many samples; it appears to be common in fossil deposits. Certain species illustrated in the literature could, we feel, be placed in this genus. Pantocsek’s illustrations of Fragilaria inflata Pant. (F. brevistriata var. inflata (Pant.) Hust.) show an extremely wide central sternum with marginal striae (Pantocsek. 1902: 79, pl. 9, figs 219,221).Additionally, F . lenoblei Manguin, F . inflatissima Hustedt, F . margarethae Schoeman and F. longirostris Frenguelli would all repay further investigation. Pseudostaurosira brevistriata (Grun. in Van Heurck) Williams & Round, comb.nov. Basionym: Fragilaria brevistriata Grunow in Van Heurck 1880-5:157,pl. 45, fig. 32. Type locality: ‘Eaux douce - Bruxelles (Delogne). Type no. 318’. Type slide: BM 26629. Frustules rectangular, forming chains. Valves slightly cruciform, 2-5p m in breadth, 12-28p m in length. Striae uniseriate consisting of a few large round to ovoid areolae; no more than four per stria at the centre, less at the poles; 13-17in 10 pm. Closing plate delicate and highly branched. Sternum wide along the entire length of the valve. Apical pore-fields consisting of a few pores. Rimoportulae absent. Mantle plaques present along the mantle edge. Spines situated along the valve edge usually in a somewhat plain region of the valve, enlarged at the tips (Figs 28-31). Loseva (1982,pl. 24,figs 1 ,2) illustrates details of the closing plate which somewhat resembles a vola. It is not clear if Loseva’s specimens are P. brevistriata but it is possible that they belong in this genus. Also included in this genus:Pseudostaurosira zeilleri (HCrib.) Williams & Round, comb.nov. Basionym: Fragilaria zeillm’ Heribaud 1902:26, pl. 10, fig. 9. Type Locality: Joursac. Type slide: BM 68398. Serieyssol & Blanc (1983)have examined specimens of P. zeilleri from the type locality of Joursac. Their specimens have a very wide central area, pore fields and linking spines. Each spine is across an areolae.


REVISION OF THE GENUS FRAGIJARIA

277

Figs 28-31. Pseudostaurosiru brevistriuta. Fig.28. Side view of valve showing single row of areolae beneath spines. Bar = 1 pm. Figs 29-31. Inside views. The small apical pore fields can be seen. Bars: Fig.29 & 30 = 4 pm. Fig.31 = 1 pm.

Gasse (1980) has also published several SEM's of this species. The areolae are reasonably large relative to the surface area of the valve face; in general, there is an areola on the valve face and another on the mantle with the spine lying between the two. This is more clearly seen in the SEMs of F. zeillmi var. elliptica Gasse (1980, fig. 7). The closing plate is missing from her specimens. Gasse suggested that this species is synonymous with F. estherae Hajos and F . transylvanica Pant. Gasse's specimens are quite different from those of Serieyssol & Blanc (1983). Nevertheless, they all seem to belong in this genus. Pseudostaurosira pseudoconstruens (Marciniak) Williams & Round, comb.nov. Basionym: Fragilaria pseudoconstrums Marciniak 1982: 163, pl. 1, figs 1, 2; pl. 2, fig. 4.


278 D. M. WILLIAMS AND F. E. ROUND

Pseudostaurosira robusta Williams & Round, comb. m. (Figs 32,33,35). Basionym: Frag’luria construens var. binodis f. robusta Fusey 1951: 34, pl. 1, fig. 2. Fragiluria robusta (Fusey) Manguin 1954: 78, pl. 1, fig. 6a, b, non F . robusta Hustedt in A. Schmidt 1913: pl. 297, figs 79-83 nom. nud. Fragiluria pseudoconstruens var. bigibba Marciniak 1982: 164, pl. 1, figs 3-6; Marciniak 1986: pl. 2, fig. 3. Type locality: ‘Etang du Pellinee, pH 10, plancton.’ Pseudostaurosira pseudoconstruens is distinguishable from F . pseudoconstruens var. bigibba not only on the shape of the valve but also by the orientation of the spines. Marciniak (1986) suggested that it could be synonymous with F . robusta (Fusey) Manguin. We agree with this combination and it is evident that the correct name should be P. robusta. Punctastriata Williams & Round, gen.nov. Frustules rectangular (Figs 40,42,43), sometimes in short chains. Valves linear-elliptical (Figs 38,42-44), sometimes with central inflation. Striae level with (Figs 39,40), or slightly depressed (Figs 42,43) below the valve surface. Closing plates with a distinctive, highly silicified, regular net of transapical and apical bars (Figs 39-43). Spines situated along the valve face/mantle junction on the interstriae or across the striae or on both; spines of varied form. One apical pore-field present, usually small. Valve mantle plaques present, usually many and small. Rimoportulae absent. Cingulum consisting of several open, plain, ligulate copulae. Valvocopula not larger than the copulae. Plastids unknown. Frustulum cingulari aspectu rectangulare, catenas formant. Lamellae claudentes complexae tigillis fulcrantibus. Area axialis brevis solitarius. Type: Punctastriata Zinearis Williams & Round, s p . m . (Figs 38-42). This genus is quite difficult to identify in the LM, and even at the SEM level. It has been identified as Fragiluria (e.g. as either Fragiluriapinnata (Rosen & Lowe 1981, p. 294, fig. 4; LangeBertalot & LeCohu 1985, p. 220, fig. 37; Kobayasi & Yoshida 1984) or else Fragilamapinnata var. Zunccetula (Kobayasi & Yoshida 1984; Loseva 1982, t. 26, figs 1-3)) or as Opephora in the literature (cf. Opephora Zinearis Sherman & Patrick, 1981 which requires SEM study to ascertain its true identity). With this difficulty, it is impossible to trace original names that have been used to describe these taxa, and without an SEM study of all the relevant material it appears necessary at this stage to describe them as new. Punctastriata Zinearis Williams & Round, sp.nov. (Figs 42-44). Type locality: Lake, Toba, surface of submerged sand, Samosir Island, Shell Bay, shallow water 21.2.84, P.A. Sims & T.B.B. Paddock. Holotype slide: BM 81404 Valves linear-elliptical, 1.5-3.0 p m in breadth, 12-20 p m in length. Striae 1-3 in 10 pm. Spines situated along the valve face/mantle junction on the interstriae and across the striae; spines short, pointed, usually paired. Single apical pore-field present. Many small valve mantle plaques. Plastids unknown. Valve lineari-lanceolatae, apicibus late rotundatae, 12-20pm longae, 1.5-3.Opm latae. Punctastriata ovalis Williams & Round, sp.nov. Type locality: Water trough, Burrington, Somerset, U.K. Holotype slide: BM 81405 Valves elliptical, 2-3 p m in breadth, 5-7 p m in length. Striae 1-2 in 10 pm. 5 cross-members per striae. Spines situated along the valve face/mantle junction across the striae; spines short, pointed, possibly bifurcate and hollow. Many small valve mantle plaques. Plastids unknown. Valve elliptico-lineares, apicibus late rotundatae, 5-7pm longae, 2-3pm latae.

279


REVISION OF THE GENUS FRAGIJARIA

Figs 32-37. Pseudostuurosiru. Fig.32. A short colony of P.robusta attached by short mucilage stalk. Bar = 5 pm. Fig.33. Single cell of P.robustu. Bar = 2 pm. Fig.34. Colony of a Pseudostuurosiru. Bar = 3 pm. Fig. 35. Colony of P. robustu. Bar = 4 pm. Fig. 36. Colony of P pseudostaurosiru. Bar = 3pm. Fig.37. Cell of a Pseudostuurosiru. Note the narrow apical pore field. Bar = 0.3 pm.

280



Neofragilaria Williams & Round gen.nov. Frustules rectangular, in linear (Fig.5 1) or zig-zag colonies. Valves elliptical, lanceolate or linear, with tapering, rostrate to capitate apices (Figs 45,47-50). Valves often with a central constriction (Fig.40). Striae uniseriate; often appearing to extend across the valve but usually broken by a sometimes distinct sternum; areolae with simple vela (Figs 4933). Striae extending onto the valve mantle (Fig SO), terminating short of the margin. Mantle margin with siliceous plaques (Fig.5 1). Spines present on valve face/mantle border; either complex linking structures, with large interdigitating, spathulate tips (Figs 48,52), or simple tubular projections. Apical pore fields simpIe, containing densely packed areolae and extending onto valve face (Fig. 55); occasionally lacking them. A single, polar rimoportula is present, aligned with a stria (Figs 54,56,58). Small papilliae (spinules) are sometimes present at each pole, at the junction of valve face and mantle. Cingulum consisting of 4 to 6 open, ligulate copulae, each with a single row of poroids (Figs 51,55,57). Valvocopula with a dissected pars interior and a tiny septum at the non-ligulate pole. Copulae indistinct. Plastids numerous, small, discoid. Frustulum cingulari aspectu rectangulare ,catenas formant. Area centrali parva, agri polorum apicali in superficiem valve extendentes. Cingulum ex quatuor redimiculus incompletis lingulatis constanti. Valvocopula et haud areolatae. Chromatophora numerosa parva discoidea. Type species: Frugiluriu virescens Ralfs. This genus comprises several species that have been closely associated with FrugiZuriu sensu strict0 because of their colony formation, but it is distinguished by the slight or absent sternum, the size, the number of copulae in the cingulum, the position of the spines on the valve face, the appearance of the striae and the type of pore-field. Ultrastructural evidence shows that although most species possess spines they do not necessarily link. They are usually trumpet shaped and situated at the mantle/face border. The spine orientation makes the LM image distinctive and species that should belong to this genus are recognizable from the literature. We have not made all the possible combinations as only limited material has been studied. Further investigation of this genus may reveal a geographical division as some species appear to be limited to the Northern hemisphere whilst others are from the Southern hemisphere; many others are cosmopolitan. F . bruunii Hustedt (Brazil), F . densestrim Hustedt (West Java), F . juvunicu Hustedt (West Java), F . nitzschioides Grunow in Van Heurck (Brazil, North Amerita, Europe??), F . sioli Hustedt (Brazil), F . obtusu Hustedt (Venezuela) and F . sublineutu Hustedt in A. Schmidt (West Africa) may all be members of this genus. Neofrugihriu virescens (Ralfs) Williams & Round, cornb.nbu. Basionym: Fr&Zuriu virescens Ralfs 1843: 110, pl. 2, fig. 6. Type locality: ‘Cold bath, Tunbridge Wells, Mr. Jenner. Madron and Chyandal Moor near Penzance.’ Type slide: BM 81303. Frustules rectangular, in linear colonies. Valves linear with tapering, rostrate to capitate apices, 5-10 p m in breadth, 12-120 p m in length. Striae uniseriate; alternate, occasionally extending across the valve face; areolae with simple closing plates. Sternum central. Striae extending onto the valve mantle terminating short of the margin, 12-19 in 10pm. Mantle margin with siliceous plaques. Spines present on valve face/mantle border, complex, interdigitating, and having spathulate tips. Apical pore fields simple, of densely packed areolae, extending onto the valve face. A single, polar rimoportula is present, aligned with a stria. Cingulum consisting of between 4 to 6 open, ligulate copulae, each with a single row of poroids. Valvocopula with a dissected pars interior and a tiny

Figs 38-42. Punccasniacalzmuris. Fig.38. Complete valve. Bar = 2.5 pm. Fig.39. External view of areolae and short conical spines. Bar =0.65 pm.Fig.40. Valve mantle with small plaques and copdlae. Bar = 4 pm. Fig.41. Internal view of areolae. Bar = 1.5 pm. Fig.42. Cell showing striae across and between the areolae. Bar = 1.4 pm. Figs 43-44. P.ovaZis. Fig.43. Cell showing the complex spines situated on the areolae. Bar = 1 pm. Fig.44. Internal view. Bar = 1 pm.



281


282


septum at the non-ligulate pole. Copulae not distinct from valvocopula. Plastids numerous, small, discoid (Figs 45,48(?),50,51,54-58). Other species of this genus are: Neofrugilariu bicuflitutu (Mayer) Williams & Round, comb.nov. Basionym: Frugihriu bicupitutu Mayer 1916: 21, pl. 1, figs 26,27. Type locality: '...Aufsammlungen von der Kosseine ferner in einem Wiesenbachlein bei Ebnath und im Muhlweiher bei Fuchsmuhl.' Neofrugilariu consm'ctu (Ehrenb.) Williams & Round, comb.nov. (Figs 46,52,53). Basionym: Frugilariu constrictu Ehrenberg 1843b: 415, pl. 1/1, fig. 21; pl. 3/6, fig. 10. Type locality: Falkands Inseln. [Malvinen - oder Falklands-Inseln (5 1-53" S.B. , 57-62" W.L.v.Gr.)] (pl. 1/1, fig. 21); Moctezuma Fluss [ Moctezuma-Fluss, 5000 fuss(?) uber der Meersesflache] (pl. 3/6, fig. 10). Two localities are given in the type description, both being in the Southern hemisphere. It is possible that Ehrenberg's taxon is not synonymous with that currently accepted as N . constrictu. However, without inspection of the type material it is impossible to make any judgements except to compare Ehrenberg's illustrations , which are uninformative, with our pictures. Neofrugiluriu strungulatu (Zanon) Williams & Round, comb.nov. (Figs 47,49). Basionym: Synedru strungulatu Zanon 1938: 587, fig. 14. Synonym: Frugilariu strungulatu (Zanon) Hustedt 1949: 62. Type locality: In aquis dulcibus, in regione lacus Kivu in Congo Belga Africae aequatorialis. The identity of this species is not clear since two closely related taxa are confused in the literature. Zanon's original illustration of Synedru strungulatu depicted a linear valve with capitate poles and no spines along the valves margins. When Hustedt examined specimens of this diatom from his African samples, he illustrated the species with marginal spines and with the valve distinctly tapering from the centre to the poles. Hustedt effected his transfer on the basis of the presence of spines. Later, Hustedt described a species from Java, Frugilariujuvunicus Hust., that was in many respects more similar to Zanon's original drawings than those Hustedt included in his African studies. Recently, Carter & Denny (1987) described Frugilariu telum Carter & Denny from Sierra Leone. They distinguished their species from F . juvunicus by the lack of marginal spines and the lack of a pseudoraphe (sternum). Clearly, this is an interesting group of species that require further study. Significantly, all the records of this complex are from Africa with the exception of one record from Florida, U.S.A. (Scherer, in Gasse 1986). Neofrfagilaria ucidobwnticu (Charles) Williams & Round, comb.nm. Basionym: Frugilariu acidobionticu Charles 1986: 36, figs 1,2. Type locality: Adirondack Park, New York. Holotype: PH AGC 54250 Charles (1986) described a new and unusual species, F. ucidobionticu, from North America. Dr. Charles was kind enough to supply us with material of F . ucidobionticu. Our investigations, along with the excellent micrographs in Charles (1986), show that this species should be included in Neofrugiluriu. Neofragilaria latu (Cleve-Euler) Williams & Round, comb.nov. Basionym: Synedru purmiticu var. purusiticu f. latu Cleve-Euler (1953): 56, fig. 372a,e. Synonym: Fragilariu lutu (Cleve-Euler) Renberg (1977): 315. Type locality: Orstrask par. , Orstrask 8:4E, 1923, lectotype designated by Renberg (1977). Renberg (1977) has made a detailed study of Frugiluriu lutu; it shows all the characters of Neofrugiluriu.

DISCUSSION The genera described above have been established using a range of characters in addition to the previously used colony formation and spine structure.

283



Figs 45-51. Neofiagilariu. Fig.45. N.virescens. Bar = 5 pm. Fig.46. N.constricta. Bar = 15 pm. Fig.47. N.strangulata. Bar = 13 pm. Fig.48. A form of N. virescens. Bar = 10 pm. Fig.49. N.strangulata. Bar = 2 pm. Fig.50. N.virescens. Bar = 10 pm. Fig.51. Colony ofN.virescens. Bar = 12 pm.


284


Characters examined: (1) Valve Striation. The assumption that striation patterns in the araphid diatoms are relatively uniform is far from true. Amongst the species discussed above, there are distinct generic differences. Fragilaria semu strict0 has simple, uniseriate striae with the ribs more or less parallel but unequal in width. Little is known of the closing plate structure. However, it seems likely that it will also be simple due to the lack of space between the ribs and cross-members. This particular striation pattern is shared with Asterionella Hassall (Korner 1970), Diatoma (Odontidium)Kiitz. and Hunnuea Patrick (pers. obs.). It is also shared, but to lesser degree, by Neofragilaria, although here the ribs are more evenly spaced. Staurosira, Pseudostaurosiru, Staurosirella and Punctastriata are altogether different. Staurosira has externally raised ribs but retains the small cross-members and hence a simple closing plate. Pseudostaurosira has much thicker ribs which extend from a rather ill-defined sternum. The closing plates are rather more complex and the areolae are situated adjacent to the valve/mantle junction. In contrast, Staurosirella, whilst having the thicker ribs and complex closing plates, has a well defined sternum and many more cross-members between the striae ribs. In some respects this is similar to Punctastriata, but in the latter the striae are highly divided within each pair of adjacent cross-members. The four types are neatly contrasted in the SEM’s given in Rosen & Lowe (1981). The closing plate pattern in Staurosira is similar, in some respects, to that in Tabularia (see Williams & Round 1986) and there is no doubt that these two may have been confusedin the LM. They are quite clearly distinguishable in the SEM by observing the apical pore fields. A case in point is ‘Frag’laria’fonticola,a species from Java and South America. It is not clear whether this belongs in Tabularia or Staurosira - examination of the pore fields by SEM is required. (2) Linking spines. The type of linking spine is a variable feature throughout all the genera described above. This probably explains why previous attempts to utilize this character have failed. It is quite possible that, as Lange-Bertalot (1980) has suggested, the presence of spines is coupled with habitat. However, we feel a more detailed study of the linking spines may yet reveal taxonomicallyimportant characters. (3) Apical Pore fields. Only Fragilaria s m strict0 has the distinct ocellulimbus but it is weakly developed. All the other genera have a simpler type of pore-field or lack such structures entirely. The presence of a simple pore-field is not a character that can be used with great reliablity as certain species in each genus are without it, e.g. Neofi-agilariaacidobiontica, Staurosira elliptica, Staurosirella pinnata. (4)Rimoportulae. Most species of Fragilaria sensu stricto and Neofragilaria possess a single polar rimoportula. In Fragilaria the rimoportula is usually situated on the valve face. In some instances it appears on the valve mantle (e.g. Fragilaria cupucina var. mesokptu, in Hoagland & Rosowksi 1978) and in other instances it appears to be missing (e.g. Neofiugiluriu latu, in Renberg 1977). A study of the incidence of rimoportulae is necessary as the absence of a rimoportula in some specimens may not be significant if others possess one. Staurosira, Staurosirella, Pseudostaurosira and Punctastriata all lack rimportulae. (5) Girdle. The girdle structure in all the above genera is rather simple, being a set of open, ligulate copulae. Once again, Fragilariu sensu stricto and Neofragilaria share a similar construction, the copulae having a single row of poroids extending around each copula, situated just on the inside of the pars interior; these are often slightly obscured in situ. Additionally, the valvocopula is undifferentiated. There are very few copulae in these genera. In contrast, Staurosira, Staurosirella, Pseudostaurosira and Punctastriata have numerous non-areolate copulae with an extremely deep valvocopula. The differences in structure between genera is such that they can be distinguished on this basis. (6) Plastids. Plastid morphology has not been studied in detail. All genera, except Neofragihria possess two parietal plates lying alongside the valve. Examples are Fragilaria capucina and its vars. acuta and mesokpta, (Ott 1900, Mereschkowsky 1902, Heinzerling 1908), Frag‘la,ria crotonensis (Mereschowsky 1902, Crawford et al. 1985), Staurosira construens (Pfitzer 1871), Staurosirella pinnata (Pfitzer 1871) which are all reported with two plates. Neofrugilariavirescens alone is reported

285



Figs 52-58. Neofiagilaria. Fig.52. N.constricta. Showing copulae with rows of pores. Bar = 1.3 pm. Fig.53. N.constricta. Centre of valve showing areolae with centrally perforate cribra. Bar = 1.3pm. Fig.54. N.virescens. Internal view showing the single rimoportula. Bar = 4.2 pm. Fig.55. N.virescens. Cell apical pore field and porate copulae. Bar = 3 pm. Figs 5658. Internal views of N.virescens. Fig.58 shows the unusual apical valve margin seen in some valves. Bars: Figs 56 & 58 = 5 pm. Fig.57 = 1 pm.


286 D. M. WILLIAMS AND F. E. ROUND with many smaller plates (Heinzerling 1908). There have been no observations on plastids in Pseudostaurosira or Punctustriata. It is clear that the range of character variation will allow distinctions to be made at the generic level. The situation is similar in some respects to that of Sywdra, where the two characters to which most taxonomic value has been attached, i.e. the distribution of rimoportulae and the presence of linking spines, fail to suggest any divisions congruent with additional character information. On examination of published SEM’s and, indeed, drawings, we tend to the conclusion that further groups remain to be discovered. In particular, we are drawn to two contrasting areas. The first is a group of species with a central stauros. Preliminary examination by LM of F . aethiopica West suggests it may not be an araphid diatom but this will require further investigation; other species with a central stauros are F . gesneri Hustedt, F . leptostauron var. stauronifomzis Woodhead & Tweed and F . riesgoviensis Schauderna (from German fossil deposits). The second is the ‘Fragiluria’ species described by Lange-Bertalot & LeCohu (1985) which appear to have raphe-like structures near each pole and unusual girdle components. The significance of these is not yet apparent. It is tempting, at this stage, to speculate on the relationships of these genera amongst each other and with other araphid diatoms. It is clear that Staurosira, Stuurosirella, Pseudostaurosira and Punctustriata are more closely related to each other than to Fragilariu or Neofragiluria. They share similar ungulae, the heavily silicified ribs, the reduced or absent pore field and the lack of a rimoportula. Fragiluria sensu strict0 possesses an ocellulimbus and is probably most closely related to the other genera with this feature (Williams & Round, in prep.). Neofragiluria appears to be more closely related to Diatoma, Asterionella and Hannaeu as all share a similar girdle ornamentation, valve striation and plastid structure.

REFERENCES ARCHIBALD, R.E.M. (1983). The diatoms of the Sundays and Great Fish Rivers in the eastern Cape Province of South Africa. Bibliotheca diatomologica, 1, 362 p., 34pls. CARTER, J.R. & DENNY, P. (1987). Freshwater algae of S erra Leone IV. Bacillariophyceae: Part (ii) diatoms from the coastal region of the southern province. Nova Hedwigia, 44, 229-275. CHARLES, D. F. (1986). A new diatom species, Fragilaria acidobiuntica, from acid lakes in northwestern North America. In: Diatoms and Lake Acidity. Reconstructing pH from siliceous algal remains in lake sediments. J. P. Smol, R. W. Battarbee, R. B. Davis and J. Merilainen (eds), Developments in Hydrobiology, 29, 307 pp., Dr W. Junk. CLEVE-EULER, A. (1953). Die Diatomeen von Schweden und Finnland. Kungliga Svenska Vetenskapsakadmiens handlingar, ser.4, 4 (l), 1-158. CRAWFORD, R.M., CANTER, H.M. & JAWORSKI, G.H.M. (1985). A study of two morphological variants of the diatom Fragilaria crotonensis Kitton using electron microscopy. Annals of Botany, 55,473485. DESMAZIERES, J.B.H.T. (1825) Plantes nyptogames de la France. ed.1, Lille. EHRENBERG, C.G, (1843a). Mittheilungen iiber 2 neue asiatische Lager Fossiler Infusorien-Erden aus dem russischen Trans-Kaukasien (Grusien) und Sibirien. Verhandlungender Kiiniglichen Preussischen Akademie a h Wissenschafen, 43-49. EHRENBERG, C. G. (1843b). Verbreitung und Einfluss des mikroskopischen Lebens in Siid-und NordAmerika. Abhandlungen der Koniglichen Preussischen Akademie der Wissenschaften, 1, 21 1-445. EHRENBERG, C.G. (1854). Mikrogeologie. Das Erden und falsen schaffende Wirken des unsichtbar kleinen selbststandigen Lebens auf der Erde. Leopold Voss, Leipzig. FUSEY, P. (1951). Contribution a la flore algologique de Bretagne. Bulktin de microscopie appliquie 2e ser., 1, 31- 50. GASSE, F. (1980). Les diatomkes lacustres plio-plkistocknes du Gadeb (Ethiopie). Systkmatique, paltokcologie, biostratigraphie. Revue Algohgie, m h . hars-shie, 3 , 249 pp., 62 pls. GASSE, F. (1986). East African diatoms. Taxonomy, ecological distribution. Bibliotheca diatomologica, 11, 201 pp, 44 pls. GRUNOW, A. (1862). Die osterreichischen Diatomeen nebst Anschluss einiger neuen Arten von andern Lokalitaten und einer kritischen Ubersicht der bisher bekannten Gattungen und Arten. Erste Folge.

P



287

Epithemieae, Meridioneae, Diatomeae, Entopyleae, Surirellkae, Amphipleureae. Verhndlungender hiserlich-koniglichen zoologisch-botanischen Gesellschaft in Wien 12, 315-472. HASLE, G.R. & SWERTSEN, E.E. (1981). The marine diatoms Fragihria striatula and F . hyalina. Sh.iae, 14, 110-118. HAWORTH, E.Y. (1974). A scanning electron microscope study of some different frustule forms of the genus Fragihria found in Scottish late-glacial sediments. British Phycologicul Journal 10, 73-80. HEINZERLING, 0. (1908). Der Bau der Diatomeenzelle. Bibllotheca botanica, 69, 88pp., 3 pls., Stuttgart. HERIBAUD, J. (1902). Les Dktombes d’Auvergne. Libraire des Sciences Naturelles. 79 pp., 2 pls. HOAGLAND, K.D. & ROSOWSKI, J.R. (1978). Valve and band morphology of some freshwater diatoms I. Fragilmia capucina var. mesolepta. Journal of Phycology, 14, 479-485. HUSTEDT, F. (1927-66). Die Kieselalgen Deutschlands, Osterreichs und der Schweiz unter Berucksichtigung der iibrigen Lander Europas sowie der angrenzenden Meeresegbiete. In: Dr. L . Rabenharst‘s KryptogamenF h a von Deutschland, Osteweich und der Schweiz, 7(2), 177-320. HUSTEDT, F. (1930). Bacillariophyta. In: Die Suswasser-flora Mittehropas (A.Pascher, ed.), 10 (2nd edition). G .Fischer , Jena . HUSTEDT, F. (1949). Susswasser-Diatomeenaus dem Albert-National park in Belgisch-Kongo. Exploration du Parc National Albert, Mission H . Damas (1935-1936), 199 pp. KITTON, F. (1869). Notes on New York diatoms with description of a new species Fragihria motonensis. Science Gossip, 5, 109-110. KOBAYASI, H. & YOSHIDA, M. (1984). Diatoms found in small concrete pools as suitable material for observation in junior high school biology. Bulletin of the Tokyo Gakugei University, sect. 4,36, 115-143. KORNER, H. (1970). Morphologie und taxonomie der Diatomeengattung Asterionella. Nova Hedwigia, 20, 557-724. KUTZING, F. (1833a). Synopsis Diatomacearum. Linnaea, 8, 529-620. KUTZING, F. (1833b). Algae aquae dulcis Germanicorum. 15 decas.No pagination. Halle. KUTZING, F. (1844). Die kiesekchligen Bm‘lhrien o h Diatofneen. Nordhausen, 152 pp., 30 pls. LANGE-BERTALOT, H. (1980). Zur systematischen Bewertuhg der bandformigen kolonien bei Navicuh und Fragdaria. Nova Hedwigia 33, 723-787. LANGE-BERTALOT, H. & LE COHU, R. (1985). Raphe like vestiges in the pennate diatom suborder Araphidinae. Annales de limnologie, 21, 213-220. LOSEVA, E. I. (1982). Atlas pozdmepliotsenvykh Diatomei Prikam’ya [Atlas of late Pliocene diatoms of the Karma region]. XI Kongessu INQUA, Moskva, Nauk: Leningrad. [XIINQUA Congress, Moscow], 204 PP. LYNGBYE, H. C. (1819). Tentamen hydrophytobgiae Danicae. Gyldendal: Copenhagen, 248 pp. MANGUIN, E. (1954). Contribution ti la connaisance biologique des boues lacustres Lac Pavin (Puy-deD6me). Annales de I’Ecole nationale des eawc et f m h et de la station de recherches et exphiemes fmestieres, 14, 69-83. MARCINIAK, B. (1982). Late glacial and holocene new diatoms from a glacial lake Przedni Staw in the Pie6 Staw6w PolskichValley, Polish Tatra Mts. Acta Geob&a Scientiarum Hungaricae, 25, 161-171, MARCINIAK, B. (1986). Late quaternary diatoms in the sediments of Przedni Staw Lake (Polish Tatra Mountains).Hydrobiologia,143, 255-265. MAYER, A. (1916). Beitrage zur Diatomeen Bayerns. I. A. Bacillariales aus dem Fichtelgebirge und angrenzanden Gebieten. B. Bacillariales aus dem bayeriscden Walde. Dennkschrzfien der K. Bqm’schen botanischen Gesellscha..zu Regensburg 13, 1-99. MERESCHKOWSKY, C. (1902). Les types de l’endochrome des diatomees. Scripta botanica Hurti Universitatis imperialis Petropolitanae 21, 107-193. OTT, E. (1900). Untersuchungen uber den Chromatophoren-Bau der Shsswasser-Diatomeen und dessen Beziehungen zur Systematik. Sitmngberichte der Akademie der Wissenschaften.Mathmtisch-Natunoissenschaftliche Classe Wien,109, 769-801. PANTOCSEK, J. (1902). Kieselalgen oder Bacillarien des Balaton. Resultate wissmchaftlichen erjimschung des Balatonsees, sec. 1, 112 pp., 17 pls. PATRICK, R. 81REIMER, C.W. (1966). The diatoms of the United States, exclusive of Alaska and Hawaii, Vol. 1. Monographs. Academy of Natural Sciences of Philadelphia, 13, 688 pp. PETERSEN, J. B. (1938). Frag‘hria intmedia - Synedra vaucheriae? Botaniser Notiser, 1938, 164-170. PETIT, P. (1877). An essay on the classification of the Diatomaceae. Monthly Microscopical Journal, 18, 1014, 65-77.


288


PFITZER, E. (187 1). Untersuchungen uber Bau und Entwicklung der Bacillariaceen (Diatomaceen). Botanische Abhandlungen (J. Hanstein, ed.) 2, 189 pp. PODZORSKI, A. C. (1985). An illustrated and annotated checklist of the diatoms from the Black River Waterways, St. Elizabeth, Jamaica. Bibliotheca diatumologica, 7, 177 pp. POULIN, M., BERARD-THERRIAULT L. & CARDINAL, A. (1984). Les diatomCes benthiques de substrats durs des eaux marines et saumltrks du QuCbec 3. Fragilarioideae (Fragilariales,Fragilariaceae). Naturaliste Canadiene 111: 349-367. POULIN, M. , BERARD-THERRIAULT, L. & CARDINAL, A. (1986). Fragilaria and Synedra (Bacillariophyceae): A morphological and ultrastructural approach. Diatom Research 1, 99-112. RALFS, J. (1843). On the Diatomaceae. Annals and Magazine of Natural History 12, 104-111. RENBERG, I. (1977). Fragilaria lata, a new diatom species. Botaniser Notiser, 130, 315-318. ROSEN, B.H. & LOWE, R.L. (1981). Valve ultrastructure of some confusing Fragilariaceae. Micron, 22, 293-294. ROSS, R., COX, E.J., KARAYEVA, N.I., MANN, D.G., PADDOCK, T.B.B., SIMONSEN, R. & SIMS, P.A. (1979). An amended terminology for the siliceous components of the diatom cell. Nova Hedwigia, Beiheft, 64, 513-533. ROUND, F.E. (1979). The classification of the genus Synedra. Nova Hedwigia, Beiheft, 64, 135-146. ROUND, F.E. (1984). The circumscription ofSynedra and Fragilaria and their subgroupings. In:- Proceedings of the Seventh Zntmtional Diatom Symposium (D.G. Mann, ed.), 241-253. Otto Koeltz, Koenigstein. SCHMIDT, A. (1913). Atlas der Diatomaceen-kunde. R. Reisland, Leipzig. SCHOEMAN, F.R. (1974). A systematical and special ecological study of the diatom flora of Lesotho with special reference to the water quality. National Institute of Water Research, 355 pp. SCHUMANN, J. (1867). Preussiche Diatomeen. Schriften der Physikalisch-iikonomischen Gesellschaft zu Kijnigsberg, 8, 37-68. SERIEYSSOL, K.K. & BLANC, P. (1983). Preliminary attempts of transmission work using a scanning electron microscope applied to diatoms. Revue de micropalontologze, 26, 54-59. SHERMAN, J.W. & PATRICK, R. (1981). The waters of Merom: A study of Lake Huleh. 7. Diatom stratigraphy of the 54-M core. Archiv fur Hydrobiologie, 92, 199-221. SMITH, W. (1856). Synopsis of British Diatomaceae. Volume 2, John van Voorst, London, 107 pp., pls 3260. SOVEREIGN, H.E. (1958). The diatoms of Crater Lake, Oregon. Transactions of the American Microscopical Society, 77,96-134. VAN HEURCK, H. (1880-1885). Synopsis des diatmies de Belgiques. Atlas, 1880-1883, Texte, 1885. Anvers, J. Ducaju and Co. WILLIAMS, D.M. (1986). Comparative morphology o f some species of Synedra with a new definition of the genus. Diatom Research, 1, 131-152. WILLIAMS, D. M. and ROUND, F.E. (1986). Revision of the genus Synedra Ehrenb. Diatom Research, 1, 313-339. ZANON, D.V. (1938). Diatomee della Regione del Kivu (Congo Belga). Commentationes Pont$ciae academiae scientiamm 2, 535-668.