OCCURRENCE OF THREE NITZSCHIA (BACILLARIOPHYCEAE) TAXA WITHIN COLONIES OF TUBE-FORMING DIATOMS1

In benthic samples from the unchannelized Missouri River, the diatoms Nitzschia dissipata (Kütz.) Grun., N. filiformis (W. Sm.) Schütt and N. pseudofonticola Hust. were observed within the mucilage tubes of four tube-forming diatoms: Cymbella prostrata (Berk.) Cl., C. prostrata var. auerswaldii (Rabh.) Reim., Navicula tripunctata var. schizonemoides (V.H.) Patr., and Nitzschia filiformis. Microscopical observations of live and preserved specimens indicated that “invasion” by Nitzschia occurred primarily in older tubes. Data are presented on the environmental conditions in which the tube-formers and their cohabitants have been found.     

COMMUNITY STRUCTURE DYNAMICS OF EPILITHIC AND EPIPHYTIC DIATOMS IN A MISSISSIPPI STREAM1

Epilithic and epiphytic diatoms were collected monthly from 18 June 1979 through 19 May 1980 from both shaded and unshaded sites of Sessums Creek, a shallow, oligotrophic and strongly alkaline stream in northeastern Mississippi. The dominant macroalgae were filamentous green algae belonging to the non-mucilage producing genera Cladophora and Rhizoclonium. Ninety taxa were identified with Navicula minima Grun. and Nitzschia dissipata (Kütz.) Grun. accounting for 50% of all valves counted. Other important taxa were Navicula menisculus var. upsaliensis (Grun.) Grun., N. cryptocephala var. veneta (Kütz.) Rabh., Achnanthes minutissima Kütz. and Cymbella turgida (Greg.) Cl. With few exceptions, the more dominant taxa were equally abundant in the shaded and unshaded sites and also in the epilithon and epiphyton. Species diversity (H') and the number of taxa in a sample in all four habitats showed an identical pattern, being lowest in winter and highest in fall. No one pair of habitats was more structurally similar than any-other pair when compared by a similarity index (SIMI). Apparently, differences in light intensity and substrate type had little effect on diatom distribution in Sessums Creek and it was concluded that the locality sampled supported a single, nearly homogeneous diatom community.     

Geothermal diatoms: a comparative study of floras in hot spring systems of Iceland,New Zealand,and Kenya

Diatom floras were examined from geothermal environments in three contrasting tectonic settings. These included subduction-related acid and alkaline springs in New Zealand; alkaline springs along a divergent plate boundary on Iceland; and alkaline springs in the Kenya Rift. These shallow (<1 cm) aquatic environments vary considerably (e.g., temperature: 21.3–99°C; pH: 2.1–9.65; 56.41–643 mg l⁻¹ SiO₂). Diatoms form an important component of geothermal floras at temperatures of <45°C. The floras from New Zealand are distinguished by the common occurrence of Pinnularia. Icelandic springs have a variety of Fragilariaceae. Navicula and Anomoeoneis are most common in the Kenyan springs. Statistical analyses suggest that the diatoms cluster into seven major groups. The most common taxa include: Achnanthidium exiguum v. heterovalvum (Kras.) Czarn., Anomoeoneis sphaerophora (Ehrenb.) Pfitz, Brachysira brebissonii f. thermalis Grun., Caloneis bacillum (Grun.) Cl., Craticula cuspidata (Kütz.) Mann, Diadesmis confervacea Kütz., Epithemia argus (Ehrenb.) Kütz., Frustulia rhomboides (Ehrenb.) DeT., Hantzschia amphioxys (Ehrenb.) Grun., Navicula tenelloides Hust., Nitzschia amphibia Grun., Nitzschia inconspicua Grun., Nitzschia invisitata Hust., Nitzschia frustulum (Kütz.) Grun., Nitzschia sigma (Kütz.) W, Smith., Pinnularia chapmaniana Fog., Pinnularia appendiculata (Ag.) Cl., Pinnularia molaris (Grun.) Cl., Pinnularia acoricola Hust., Rhopalodia gibberula (Ehrenb.) O. Müll., Staurosira construens v. venter (Ehrenb.) Ham., Staurosira elliptica (Schum.) Will. & Round, and Staurosirella pinnata (Ehrenb.) Will. & Round. Canonical correspondence analysis shows clear correlations between species, alkalinity, pH, and conductivity, with less strong correlations for silica and temperature. Other factors include substrate type, current velocity, and light conditions. The preservation potential of host deposits varies considerably, being lowest for springs on clastic deltas and highest where travertine or sinter is accumulating. Handling editor: J. Padisak     

A prostrate species of myricaria in Eastern Himalaya and Yunnan

Summary

Under the name Myricaria germanica var. prostrata two species, both distinct from M. germanica (L.) Desv., have been confused, namely M. prostrata Hook. f. & Thoms. (syn. M. hedinii Paulsen) and M. rosea W. W. Smith, hitherto considered endemic to Yunnan but now known to extend westward to central Nepal.     

Influence of urea and farmyard manure compost as N source on symbiotic association between <Emphasis Type="Italic">Rhizobium leguminosarum</Emphasis> (MTTC 10096)<Emphasis Type="Italic">—Neptunia prostrata</Emphasis> (Lam.) Baill

Growth, biomass production, nitrogen fixation and nodulation in Neptunia prostrata (Lam.) Baill. is affected differently by various N sources and concentrations but the subject needs to be discussed in more depth. Effects of urea and farmyard manure compost (FYMC) as N source on the symbiotic association between Rhizobium leguminosarum MTTC10096—Neptunia prostrata (Lam.) Baill., biomass production, nitrogen accumulation, etc., at three different concentrations in loamy soil culture were investigated. The total N in both urea and FYMC were of equal proportion, but FYMC was more beneficial in overall performance of Neptunia prostrata plant. Nodule number and biomass were greatly depressed but plant length and weight showed slight increase by the higher N concentration in all the samplings. The study revealed that higher concentration of urea has more negative effect on nodule biomass and number than FYMC as compared to control. The plants also showed better N percent accumulation on the application of FYMC than urea. The overall performance of the plant was more pronounced on FYMC application as N source. It might be due to the presence of other vital nutrients in FYMC other than N, essential for both the host plant and microsymbiont. This aspect, however, awaits further experimental proof.     

DIATOM ASSEMBLAGES OF STREAMS INFLUENCED BY WILDFIRE1

The Greater Yellowstone Area ecosystem experienced major wildfires in 1988, resulting in a substantial number of catchments being burned. We studied diatom assemblage structure at 14 sites over 5 years in catchments ranging from 0 to over 90% burned. Coefficients of variation for selected physical measures provided a good assessment of the degree of disturbance experienced by the various sites and correlated highly with percentage of catchment burned. Principal components analysis quantitatively estimated the degree of temporal change in diatom assemblages at a site. The more extensively burned catchments showed the greatest amount of structural change in diatom taxa among years. Navicula permitis Hust. and Nitzschia inconspicua Grun. were predominant in the heavily disturbed systems, whereas Achnanthes minutissima Kuetz., A. lanceolata (Breb.) Grun., Rhoicosphenia curvata (Kuetz.) Grun. ex Rabh., and Diatoma hiemale var. mesodon (Ehr.) Grun. were common in less disturbed streams. The results demonstrate that recovery trajectories of lotic diatom assemblages following major landscape-scale disturbances are a function of disturbance intensity resulting from differences in catchment characteristics.     

SYSTEMATICS OF TRIPSACUM DACTYLOIDES (GRAMINEAE)

Tripsacum dactyloides (L.) L. extends across the range of this genus from about 42°N to 24°S latitude in the New World. It is recognized to include T. dactyloides var. dactyloides (North America), var. meridonale deWet et Timothy (South America), var. hispidum (Hitchc.) deWet et Harlan comb. nov. (Mesoamerica) and var. mexicanum deWet et Harlan var. nov. (Mesoamericana). The genus is divided into sections Tripsacum and Fasciculatum. Mesoamerican members of section Tripsacum are classified into T. bravum Gray, T. dactyloides (L.) L., T. intermedium deWet et Harlan spec, nov., T. latifolium Hitchc., T. manisuroides deWet et Harlan spec. nov. and T. zopilotense Hern,*** et Randolph. A key to the species of section Tripsacum is presented.     

A revision of the moss genus Gymnostomiella Fleisch.

Abstract

A taxonomic revision of the moss genus Gymnostomiella Fleisch. recognizes five species and one variety, viz. G. burmensis Bartr., G. erosulum (C. Müll. ex Dus.) Arts, G. longinervis Broth., G. monodii P. Yarde, G. vernicosa (Harv.) Fleisch. var. vernicosa and G. vernicosa var. tenerum (C. Müll. ex Dus.) Arts. Gymnostomiella tenerum (C. Müll. ex Dus.) Arts is reduced to a variety of G. vernicosa and G. tanganyikae De Sloover is reduced to synonomy with G. erosulum.     

THE FOUR-CELLED SPECIES OF GONIUM

Stein , Janet R. (U. California, Berkeley.) The four-celled species of Gonium. Amer. Jour. Bot. 46(5): 366–371. Illus. 1959.—A review is given of the 4-celled species of Gonium O. F. Müller 1773 (Volvocales). From a study of clonal isolates, it has been possible to distinguish 2 distinct species, G. sociale (Dujardin) Warming 1876 and G. sacculiferum Scherffel 1904. The former may be divided further, on the basis of vegetative morphology and sexual reproduction, into 2 varieties: var. sociale and var. sacculum var. nov., and a possible third variety, var. majus Hansgirg 1888. A brief discussion of morphology and sexual reproduction (reported for the first time in G. sociale var. sacculum and G. sacculijerum) is presented as is a key to the species and varieties.     

Preliminary results of a classification of fifty-one selected northeastern Wisconsin Lakes (USA) using indicator diatom species

Diatom species lists were generated for 51 lakes in northeastern Wisconsin, and then classified by two-way indicator species analysis (TWINSPAN). The lakes were initially divided into two main groupings: Group I lakes which were alkaline lakes of moderate to high productivity, and Group II lakes which were acid lakes of low productivity. Group I lakes were further divided into two subgroupings, and four levels. In total, twelve indicator diatom species were recognized during the TWINSPAN lake classification, these were: Achnanthes exigua Grun., A. lanceolata var. dubia Grun., Amphora ovalis var. Affinis (Kütz.) V.H. ex Det., A. perpusilla (Grun.) Grun., Cymbella cistula (Ehrenb.) Kirch., Diploneis elliptica (Kütz.) Cl., Eunotia pectinalis (O.F. Mull.) Rabh., Fragilaria vaucheriae (Kütz.) Peters., Frustulia rhomboides var. crassinervia (Bréb. ex W. Sm.) Ross, Navicula capitata Ehrenb., N. decussis Østr., and N. scutelloides W.Sm. ex Gregory.     

中国算盘子属(叶下珠科)一些种的分类学处理

算盘子属(Glochidion J.R.G.Forst.)是叶下珠科(Phyllanthaceae)叶下珠族(Phyllantheae)中一个分类极为困难的类群。基于广泛野外考察与馆藏标本查阅,对中国该属部分物种进行分类学处理。其中,长柱算盘子[G.khasicum(Müll.Arg.)Hook.f.]与倒卵叶算盘子(G.obovatum SieboldZucc.)在中国的分布予以排除,菲岛算盘子[G.philippicum(Cav.)C.B.Rob.]在中国被发现仅分布于台湾地区;G.bodinieri H.Lév.,G.pseudo-obscurum var.glabrum Pamp.与G.pseudo-obscurum var.lanceolatum Pamp.这三个名称被处理为湖北算盘子(G.wilsonii Hutch.)的新异名;G.vaniotii H.Lév.被排除在算盘子属外,并接受为芸香科臭常春(Orixa japonica Thunb.)的异名。另外,对G.khasicum(Müll.Arg.)Hook.f.,G.obovatum SieboldZucc.,G.philippicum(Cav.)C.B.Rob.,G.pseudo-obscurum var.lanceolatum Pamp.及G.wilsonii Hutch.这五个名称进行了后选模式的指定。     

MUCILAGE TUBE MORPHOLOGY OF THREE TUBE-DWELLING DIATOMS AND ITS DIAGNOSTIC VALUE1

Colonies of Berkeleya rutilans (Trent.) Grun., Navicula pseudocomoides Hendey and N. ramosissima (C. A. Ag.) Cleve were examined using light and electron microscopy to elucidate the structure of their mucilage tubes. Each species was found to have a characteristic tube construction which could be used for identification. A summary of features on which these species can be recognized was compiled.     

ASSESSING THE RELATIONSHIPS OF AUTOSPORIC AND ZOOSPORIC CHLOROCOCCALEAN GREEN ALGAE WITH 18S rDNA SEQUENCE DATA1

We examined the relationships of autosporic and zoosporic taxa in the Chlorococcales by analyzing available complete nuclear-encoded small-subunit (18S) rRNA gene sequences along with two new sequences from Hydrodictyon reticulatum (L.) Lagerh. and Neochloris vigenis Archibald. Some autosporic taxa grouped with the coenobial hydrodictyacean algae and related unicellular organisms having directly opposed basal bodies. These include Scenedesmus obliquus (Turp.) Kütz. and Chlorella fusca var. vacuolata Shihira et Krauss. Other autosporic organisms, including Chlorella kessleri Fott et Novakova, C. minutissima Fott et Novakova, C. pro-tothecoides Krug., C. vulgaris Beij., Nanochlorum eucaryotum Wilhelm, Eisenbeis, Wild, et Zahn, and Prototheca wickerhamii Soneda et Tubaki, form a separate group. Of the zoosporic taxa examined, this group would appear to have the greatest affinity to organisms having a counterclockwise displacement of basal bodies, the Pleurastrophyceae. Beyond the fact that Ankistrodesmus stipitatus (=A. falcatus var. stipitatus (Chodat) Lemm.) does not group with the latter organisms, its position remains in doubt. None of the autosporic taxa appear to be closely related to chlorophycean organisms possessing a clockwise basal body displacement.     

The effects of dissolved heavy metals on attached diatoms in the Uintah Basin of Utah,U.S.A.

The relationships of diatom species to dissolved heavy metals in the streams of the Uintah Basin of Utah were studied through four seasons of 1977–1978. Niche center gradient analysis, cluster analysis and correlation analysis were performed.Achnanthes minutissima, Cyclotella meneghiniana, Cymbella minuta, Gomphonema parvulum, Navicula secreta var.apiculata, Nitzschia frustulum, Nitzschia frustulum var.perminuta, Nitzschia frustulum var.perpusilla, Nitzschia palea, andSynedra ulna appear to be indicator species of high or low heavy metal concentrations. Several other species also showed meaningful relationships to high or low heavy metal concentrations.Dept. of Physics and Astronomy, Brigham Young UniversityDept. of Physics and Astronomy, Brigham Young University     

Diatom assemblages of the Cuyahoga river,N. E. Ohio (USA)

The Cuyahoga River is a heavily polluted tributary of Lake Erie located in N. E. Ohio (USA).One hundred seventy taxa of diatoms were identified from seven locations along the Cuyahoga River. The most frequently collected diatoms from each station were Cyclotella meneghiniana, Gomphonema parvulum, Navicula cryptocephala, N. cryptocephala var. veneta, N. lanceolata, N. menisculus, N. minima, N. minuscula, N. pelliculosa, Nitzschia amphibia, N. ovalis, N. palea, and Rhoicosphenia curvata.In the most heavily damaged region of the river these widely-distributed taxa were the only frequently collected diatoms.The relatively undamaged section of the river contained 94% more taxa than the most heavily damaged section. Chief among these additional taxa were Achnanthes lanceolata, A. lanceolata var. dubia, Cocconeisplacentula, Fragilaria vaucheriae, Melosira varians, Meridion circulare, Navicula mutica var. tropica, N. symetrica, Nitzschia dissipata, Stephanodiscus astraea, and Synedra rumpens.The degree of similarity between diatom assemblages along the Cuyahoga River as measured by a modification of Sørensen's index of similarity in species-frequency of occurrence composition was related to the degree of chemical-physical water quality similarities and to the extent of similarity between areas of geologic and biologic substrates. The most dissimilar diatom assemblages usually occurred between locations that were the most dissimilar with respect to chemical-physical water quality conditions rather than to dissimilarities with respect to sediment-substrate composition.     

水玉霉(Pilobolus)属的种的重新划分

我们在过去的工作中承认水玉霉(Pilobolus)属的9个种(郑、胡,见戴,1979)。近年来我们重新分离得到了这些分类群并对它们进行了再研究。研究结果表明,尽管它们是彼此可以互相区分的分类群,但是,包括我们过去的概念在内,目前被普遍接受的用于这个属的分类的种概念太小.为了与整个毛霉目的其它属的分类系统相一致,我们把这9个分类群重新划分为由9个变种组成的5个种:晶澈水玉霉原变种[Pilobolus crystallinu (Wigg.) Tode var. crystallinus],晶澈水玉霉透孢变种新组合[P. crystallinus var.hyalosporus (Boedijn) Hu &Zheng, comb. nov.],晶澈水玉霉克莱因变种新组合[P. crystallinus var.kleinii (van Tieghem) Zheng &G.-q. Chen, comb. nov.],豆状水玉霉原变种(P. lentiger Corda var. lentiger),豆状水玉霉小型变种新组合[P. lentiger var. minutus (Speg.) Zheng &G.-q. Chen, comb. nov.],长型水玉霉(P. longipes van Tieghem),厚壁水玉霉(P. Oedipus Mont.),露水玉霉原变种[P. roridus (Bolt.) Pers. var. roridus],露水玉霉突囊变种新组合[P. roridus var. umbonatus (Butler) Hu &Zheng, comb. nov.]。水玉霉属先后报道过的种或种下分类群名称共计50个左右,其中一些异名往往被不同的作者归到不同的正名下面。为了解决它们的正确归属问题,我们对全部原始描述作了细致的文献考证然后决定其位置。对那些找不到原始描述或从原始描述中得不出结论的则作为可疑名称处理。可疑名称共计12个:Mucor obliquus Scop., M. urceolatus Dicks.;Pilobolus urceolatus Purt., P. pestis-bovinae Hallier(=P. hallierii Rivolta), P. nanus van Tieghem, P. intermedius, (Coem.) P. A. Karsten(=P. Oedipus Mont. var,intermedius Coem.), P. pullus Massee, P.proliferens McVickar, P. ramosus McVickar, P. simplex McVickar, P. lentiger forma leinii Reyn. &Laysa, P. lentiger forma minutus Reyn. &Laysa.     

Three new synonyms of Macromitrium microstomum (Hook. & Grev.) Schwägr. (Bryophyta,Orthotrichaceae), with comments on its morphological variations

Macromitrium filicaule Müll.Hal., M. pacificum var. brevisetum Thér. and M. subnitidum Müll.Hal are placed in synonymy with Macromitrium microstomum (Hook. & Grev.) Schwägr. The morphological variations of M. microstomum branch leaves, perichaetial leaves and capsules are illustrated by digital images.     

Notes on Fissidens VII–IX

Abstract

Note VII: Fissidens ah-pengae and F. aristifer spp. nov. are described and figured. The first is known from La Réunion, the second from Madagascar and La Réunion. Both belong to subgenus Aloma.

Note VIII: Fifteen new synonyms are proposed: Fissidens bryoides Hedw. var. glaucus Brid. is subsumed under F. crassipes Wilson ex Bruch & Schimp., F. comorensis Müll.Hal. under F. crispulus Brid., F. sigmocarpoides P.de la Varde under Fissidens erosulus (Müll.Hal.) Paris, F. atroviridis Besch., and F. luridus Renauld & Cardot under F. flaccidus Mitt., Moenkemeyera rarotongae Dixon and Fissidens jonesii Bizot ex Pócs under F. lagenarius Mitt. var. lagenarius, F. onraedtii Bizot nom. nud. under F. madecassus Schimp. ex Müll.Hal., F. bryum var. terrestris P.de la Varde under F. metzgeria (Müll.Hal.) Broth., F. edamensis M. Fleisch. under F. pallidinervis Mitt., F. brunnthaleri var. filipes Dixon & P.de la Varde under F. ramulosus Mitt., F. desertorum (Müll.Hal.) Paris and F. bambariensis Broth. & P.de la Varde under F. reflexus Hampe, F. usambaricus var. acutifolius P.de la Varde under F. usambaricus Broth. and F. glauculus var. circinicaulis (Cardot) P.de la Varde under F. weirii Mitt. Fissidens gedehensis M. Fleisch. is re-instated as a good species.

Note IX: Fifty-five new country and state records including F. anguste-limbatus Mitt. new to Africa. Fissidens pocsii Bizot & Dury ex Pócs is the first record of an epiphyllous species of this genus. The African distributions of F. flaccidus and F. pallidinervis are amended.     

THE DISTRIBUTION OF EDAPHIC DIATOMS ALONG ENVIRONMENTAL GRADIENTS OF A LOUISIANA SALT MARSH1

Edaphic (sediment-associated) diatoms were collected from five sites along a gradient from slightly brackish to saline marsh on 30 November 1977 and 29 April 1978. Several environmental factors change along this gradient in addition to salinity, including tidal flushing and percent organic content of the soil. A total of 112 taxa were identified, with Amphora exigua Greg., Navicula phyllepta Kütz., N. salinarum Grun., and N. tripunctata (Müll.) Bory being among the five most abundant taxa on both sampling dates. The taxonomic composition of the diatom flora was very similar to those observed for other salt marshes located along the Gulf and Atlantic coasts. Diatom taxa were generally euryhaline and distributed continuously along the gradient from brackish to saline marsh. Species diversity (H¹) and the number of taxa in a sample (S) were also similar to those reported for other North American salt marshes. The number of taxa in a sample was higher in the saline than in the brackish area on both sampling dates while species diversity was greater in the saline area only in April.     

STUDIES IN PENNATE DIATOMS: VALVE MORPHOLOGIES OF LICMOPHORA AND CAMPYLOSTYLUS1

Using scanning electron and light, microscopy, several hundred specimens of Campylostylus normanianus (Grev.) Gerloff, Licmophora abbreviata Agardh, L. gracilis var. anglica (Kütz) Per. et Per., and L. flabellata (Carm.) Agardh were examined to elucidate their valve morphology. These species were found to be heterovalvar with respect to the presence of the labiate process in the basal apices of the cell, although one was always present at the head pole of each valve. This form of heterovalvar may be one basis for partitioning the large and variable family Diatomaceae. Because of the similar valve morphologies exhibited by C. normanianus and Licmophora species examined, it is recommended that Campylostylus normanianus be placed in the older genus Licmophora, as L. normaniana (Grev.) Wahrer.