This list of diatom taxa summarizes information for over 1100 taxa and their synonyms reported in published accounts of collections made in the central United States, principally within the states of Kansas, Nebraska, and Oklahoma. It is hoped that this list will provide those working on diatom projects in this region with a base reference to help them assess the results of their research. The literature on diatoms is scattered among many journals and government publications. Although a thorough effort was made to locate all of the pertinent publications, some references possibly were missed. No records from Master's theses were incorporated into this list, and most were never published. Neither were references on fossil diatoms included (e.g., Andrews 1970; Barbour 1896; Barbour 1910; Cragin 1891; Elmore 1898a, 1898b, 1914, 1917; Hanna 1932; Selva 1976, 1981).

Specimens were not examined, so the taxa presented here are those reported in the literature or their possible synonyms. The synonyms used here were derived from publications listed in the Taxonomic References portion of the Literature Cited section. The primary references were those by Patrick and Reimer (1966, 1975), Round et al. (1990), and Van Landingham (1967-1979). Diatom systematics is an active field, with reevaluations of many taxa made every year. All diatomists do not agree with the systematic arrangements used in this list, and alternative treatments are included parenthetically for some taxa. The uncertainties generated by the current reevaluation of the systematic relationships among diatom taxa and by the misapplication of scientific names in widely used diatom references during the last 2 centuries probably have led researchers to misidentify many of the taxa listed here. Thus, to provide users of this list with the most complete information possible, the taxonomic names used in each publication are listed in this compilation with citations. The true extent of the diatom flora of the central United States can be determined only through careful examination and documentation of existing and new collections. This process is beyond the scope of this summary.

This list is subdivided into the groups of centric diatoms (Coscinodiscophyceae) and pennate diatoms, with the latter group split into those pennate diatoms without a raphe (Fragilariophyceae) and those with at least some raphe present (Bacillariophyceae). Within these 3 classes, the genera and species are listed alphabetically. Forms and varieties are listed alphabetically after the nominate variety. A question mark in front of the citation for a reference indicates that the author of the publication was not sure of his or her identification. In several of the references, authorities for the scientific names were incorrect or missing, and some Latin names were spelled incorrectly; these were corrected in this summary.

This index can be used in 2 ways. You can take the currently accepted name of a taxon to check for publications, organized by states, that included that name. Also listed are taxa that represent possible synonyms (under the heading "Synonyms" included with many entries). Entries in the list for each of these names will provide additional references in which these names were recorded. You also can start with the name of a taxon from one of the published references and find that name in the list. This will provide you with a recommended scientific name. Without checking voucher specimens, it is assumed that the author was referring to this taxon, but periodic updates to this list will be necessary. Taxa that presumably should be transferred to another genus or species, but for which no reference for the transfer could be found, also are followed by "comb. nov.?". The names of approximately 700 species, varieties, and forms that apparently comprise the diatom flora of the central United States are highlighted in bold letters.

The earliest known account of a diatom taxon from Kansas is a note in the Bulletin of the Washburn College Laboratory of Natural History (Cragin 1886):

Research on the diatoms of Oklahoma begins with "Mikrogeologie" by Christian Gottfried Ehrenberg (1856), in which he identifies taxa of diatoms and other microspecimens collected for him by surgeons at military outposts in what was then referred to as the Indian Territory. The samples were taken from the (False) Washita River near Fort Washita and Fort Arbuckle in south-central Oklahoma (north of Ardmore) and from the Neosho River near Fort Gibson (just upstream from its confluence with the Arkansas River). Despite this auspicious beginning, the next publication on recent diatoms of the state was not published for nearly a century.

During the 1940s, 3 papers were published on the diatoms of Oklahoma. The first, by Sister Maloney (1944), included taxa collected from ponds, a stock tank, a stream, and 3 aquaria. Unfortunately, collection sites were not referenced in the list of species, which includes an interesting assemblage of taxa. The taxa she reported were not included in this summary, because the aquaria probably included taxa not likely to be found in the waters of this region. In a publication that emphasized algae other than diatoms, Leake (1945) listed 11 species of diatoms among the 208 taxa she identified from Crystal Lake near Norman. During 1945 and 1946, Wallen (1949) studied the relative abundance of algae (genera only) in a pond drained, dredged, and covered across the bottom with "18 five-ton truckloads of sludge from the local sewage disposal plant" in 1943.

Soil algae and sampling methods were the topics considered in a project conducted by Willson and Forest (1957) in McClain and Cleveland counties. They recorded 3 taxa of diatoms from prairie and cropland sites. Seventeen genera of diatoms were included by Schlichting and Gearheart (1966) in a study of the effects of sewage effluent upon periphyton in an Oklahoma impoundment.

As in Kansas, diatoms were collected during the 1960s through the Water Pollution Surveillance System from the Arkansas, Verdigris, and Red rivers in Oklahoma (WPSS 1961-1963, 1966; Williams and Scott 1962; Williams 1962, 1964, 1972). Hern et al. (1979) compiled information on the plankton and trophic status of 15 reservoirs for the U.S. Environmental Protection Agency.

Several studies on diatoms in Oklahoma were conducted in the 1970s and 1980s. Wilhm and others at Oklahoma State University (Cooper and Wilhm 1975; Seyfer and Wilhm 1977; Wilhm, Cooper, and Namminga 1978; Wilhm, Dorris, Seyfer, and McClintock 1977) published research on stream periphyton in the Arkansas River drainage. These publications provided extensive lists of phytoplankton, as well as information on species diversity, biomass, and chlorophyll a.

Kennedy and Pfiester (1984) and Pfiester, Lynch, and Wright (1979) added to our knowledge of the diatoms in the North Canadian and Neosho (Grand) river drainages, respectively. Pfiester and Terry (1978) reported 24 diatom taxa from ponds in Cleveland County. Koch and Risser (1974) examined the algae (including 113 diatoms) growing on leaf detritus in a spring-fed limestone stream in Pontotoc County. Koch (1975) reported 68 taxa of diatoms, including several "salt-water" taxa, from southwestern Oklahoma. Troeger (1978, 1983) and Troeger and Menzel (1986) provided information on the diatoms of various ponds, including lists of over 100 diatom taxa derived from thousands of counted frustules (Troeger 1978, 1983).

As in Oklahoma (Kansas was somehow overlooked), the first published record of diatoms in Nebraska was compiled by Ehrenberg (1856) from samples taken from the Platte River near Fort Kearney. Later in that same century, Schofield (1892) and Webber (1889, 1890) noted a few diatom taxa, but much of the work on the diatoms of this state was a result of the efforts made by Clarence Elmore. Elmore and others examined fossil deposits to a large extent (Barbour 1896; Barbour 1910; Elmore 1898a, 1898b, 1917), but in 1921, Elmore published "The Diatoms (Bacillarioideae) of Nebraska," which is still one of the few compilations of the diatoms from a large geographic area within the United States. It contains keys, line drawings, descriptions, and regional distributions for the taxa. Elmore also was credited with the identifications of diatoms in an algal survey of sandhill lakes in Cherry County published by Andersen and Walker (1920). Patrick and Reimer (1966, 1975) examined some of Elmore's material for their monograph, in which they cited "Nebraska" and the "Plains States" with their distributions.

The diatoms of Nebraska also were included in the 2 early works on the diatoms of the United States. Wolle (1894), as he did with Kansas, included Nebraska within the range of Pleurosira laevis, and Boyer (1927a, 1927b) included that species in his "Synopsis of North American Diatomaceae."

After the "Elmore era," publications on the living diatoms of Nebraska were generally lacking during the period 1930-1960, as was the case in Kansas and Oklahoma. In 1953, Neel discussed chemical and biological aspects of the North Platte River in Wyoming and Nebraska, but his references to diatoms were not clearly correlated to specific localities. In the early 1960s, samples were obtained through the Water Pollution Surveillance System from stream sites on the Missouri, North Platte, and Platte rivers (WPSS 1961-1963, 1966; Williams & Scott 1962; Williams 1962, 1964, 1972). DeNoyelles (1967) compared the phytoplankton in a double-cell sewage lagoon, in which one pond was organically enriched. He recorded only one diatom taxon, the genus Navicula, among the algae in the ponds.

Much of the recent research conducted on diatoms in Nebraska dealt with diatoms in lakes rather than streams. McCarraher, McDonald, and Adrian (1975) summarized selected aspects of the limnology of a chain of shallow lakes created during the construction of Interstate Highway 80 in Nebraska. They reported 18 genera of diatoms. The distribution of phytoplankton and trophic status of 9 lakes in Nebraska were summarized for the U.S. Environmental Protection Agency by F.A. Morris et al. (1979).

The most recent publications on the diatoms of Nebraska have considered community structure and the role of diatom mucilage in benthic ecosystems (Hoagland, Roemer, & Rosowski 1982; Roemer, Hoagland, & Rosowski 1984; Rosowski, Roemer, Palmer, and Hoagland 1986). From 11 to 69 taxa of diatoms were reported from each collection site in these studies conducted at Pawnee, Yankee Hill, and McConaughy reservoirs and the headwaters of the Middle Fork of Maple Creek, Stanton County, Nebraska.

Biologists who have conducted phycological research in Colorado concentrated on the scenic mountainous region in the western part of the state rather than the arid eastern plains. The first report from the plains of Colorado was by Cockerell (1888). He credited Wolle with the identification of 3 diatom species from near Mace's Hole in Pueblo County. Other than this early report, only the U.S. government has published any records of diatom taxa from the eastern portion of the state. The Water Pollution Surveillance System had a collection site on the South Platte River at Julesburg, Colorado (WPSS 1961-1963; Williams 1964, 1972). M.K. Morris et al. (1979b) published results from the U.S. Environmental Protection Agency survey of the distribution of phytoplankton and trophic status of 13 reservoirs. Three of these lakes are on the eastern plains: Cucharas Reservoir, Huerfano County; Holbrook Lake, Otero County; and Lake Meredith, Crowley County.

As in eastern Colorado, few studies conducted in western Missouri have included diatoms. Ehrenberg (1856) identified diatoms from Missouri, but these were collected near St. Louis. The first accounts of diatoms from the western part of the state were published through the Water Pollution Surveillance System, which had collection stations at St. Joseph and Missouri City on the Missouri River (WPSS 1961-1963, 1966; Williams & Scott 1962; Williams 1962, 1964, 1972). M.K. Morris et al. (1979a) included Pomme de Terre Reservoir in Polk and Hickory counties; Stockton Reservoir in Dade, Polk, and Cedar counties; and Thomas Hill Reservoir in Macon and Randolph counties in their survey of phytoplankton distribution and trophic status of 6 lakes for the U.S. Environmental Protection Agency. Pamperl (1980) conducted a taxonomic survey of the diatoms of the Lake of the Ozarks. She identified 157 taxa from both the planktonic and benthic communities.

The list below summarizes the proposed classification scheme of Round et al. (1990) for those taxa reported from the central United States. It is generally similar in arrangement to that of Patrick and Reimer (1966, 1975), although this version includes several more orders, families, and genera.
 

COSCINODISCOPHYCEAE     THALASSIOSIRALES         Thalassiosiraceae             Thalassiosira         Skeletonemataceae             Skeletonema         Stephanodiscaceae             Cyclostephanos             Cyclotella             Stephanodiscus     MELOSIRALES         Melosiraceae             Melosira         Stephanopyxidaceae             Stephanopyxis     AULACOSEIRALES         Aulacoseiraceae             Aulacoseira     COSCINODISCALES         Coscinodiscaceae             Coscinodiscus         Hemidiscaceae             Actinocyclus     TRICERATIALES         Triceratiaceae             Pleurosira     RHIZOSOLENIALES         Rhizosoleniaceae             Rhizosolenia             Urosolenia     CHAETOCEROTALES         Chaetocerotaceae             Chaetoceros         Acanthocerataceae             Acanthoceras   FRAGILARIOPHYCEAE     FRAGILARIALES         Fragilariaceae             Amphicampa             Asterionella             Catacombas             Ctenophora             Diatoma             Fragilaria             Fragilariforma             Hannaea             Martyana             Meridion             Pseudostaurosira             Staurosira             Staurosirella             Synedra             Tabularia     TABELLARIALES         Tabellariaceae             Tabellaria             Tetracyclus

BACILLARIOPHYCEAE     EUNOTIALES         Eunotiaceae             Eunotia         Peroniaceae             Peronia     MASTOGLOIALES         Mastogloiaceae             Mastogloia     CYMBELLALES         Rhoicospheniaceae             Rhoicosphenia         Anomoeoneidaceae             Anomoeoneis         Cymbellaceae             Brebissonia             Cymbella             Encyonema             Placoneis         Gomphonemataceae             Gomphoneis             Gomphonema             Reimeria     ACHNANTHALES         Achnanthaceae             Achnanthes         Achnanthidiaceae             Achnanthidium             Eucocconeis         Cocconeidaceae             Cocconeis     NAVICULALES         Cavinulaceae          Cavinula         Diadesmidaceae             Luticola         Amphipleuraceae             Amphipleura             Frustulia         Brachysiraceae             Brachysira         Neidiaceae             Neidium         Scoliotropidaceae             Scoliopleura         Sellaphoraceae             Fallacia             Sellaphora         Pinnulariaceae             Pinnularia (+ Caloneis)         Diploneidaceae             Diploneis         Naviculaceae             Navicula         Pleurosigmataceae             Gyrosigma             Pleurosigma         Plagiotropidaceae             Plagiotropis         Stauroneidaceae             Stauroneis             Craticula     THALASSIOPHYSALES         Catenulaceae             Amphora     BACILLARIALES         Bacillariaceae             Bacillaria             Cylindrotheca             Denticula             Hantzschia             Nitzschia             Tryblionella     RHOPALODIALES         Rhopalodiaceae             Epithemia             Rhopalodia     SURIRELLALES         Entomoneidaceae             Entomoneis         Surirellaceae             Campylodiscus             Cymatopleura             Stenopterobia             Surirella