| Name | Author | Source | Citation | Year |
|---|
| Chlamydomonas penium | A.A. Pascher | image |
| CLOSTERIUM subgen. | HOLOPENIUM (F. Gay) M. Hirano | image |
| Closterium penium | P.F. Reinsch | image |
| Closterium pseudopenium | R.L. Grönblad | image |
| HOLOPENIUM | (Gay) Hirano | image |
| HOLOPENIUM | (Gay) W.B. Turner | image |
| HOLOPENIUM | Gay | image |
| PENIUM | Brébisson ex Ralfs | Brit. Desmid.: | 148 | 1848 |
| PENIUM | Brebisson | image |
| PENIUM | Brebisson ex Ralfs | image |
| PENIUM | | image |
| PENIUM | | image |
| PENIUM | | image |
| Penium acanthosporum | Lagerheim | Öfvers. K. [Svenska] Vet.-Akad. Förh. | 40{2}: 51, pl. I: figs. 15-17 | 1883 |
| Penium adelochondrum | Elfving | image |
| Penium adelochondrum f. minor 'West & | West' | image |
| Penium adelochondrum var. constrictum | H. Kufferath | image |
| Penium adelochondrum var. punctatum_('punctata') | Schmidle | image |
| Penium amplificatum | (Max Schmidt) M. Van Westen & P. Coesel | Phytotaxa | 52: 7 | 2012 |
| Penium annulare var. obesum | W. West | J. Bot. (London) | 29: 354, pl. 315: fig. 7 | 1891 |
| Penium annulare | W. West | J. Bot. (London) | 29: 354, pl. 315: figs. 5, 6 | 1891 |
| Penium annulatum | (Nägeli) Archer in Pritchard, | Hist. Inf. ed. 4: | 751 | 1861 |
| Penium annulatum | (Naegeli) Archer | image |
| Penium armatum | Eichler & Raciborski | image |
| Penium australe f. brevius_('brevior') | G.S. West | image |
| Penium australe f. crassior | G.S. West | image |
| Penium australe | Raciborski | Rozpr. Wydz. Mat.-Przyr., Akad. Umiej. [Kraków], ser. 2, | 2: 367, pl. VI: fig. 11 | 1892 |
| Penium australe var. minus | Hodgetts | image |
| Penium barbaricum | Claassen | image |
| Penium berginii | Archer | image |
| Penium bisporum | W.B. Turner | image |
| Penium blandum | Raciborski | image |
| Penium borgeanum f. parallelum | K. Förster & Eckert | image |
| Penium borgeanum | Skuja | image |
| Penium brebissonii | (Meneghini) Ralfs | image |
| Penium brebissonii | Ralfs | image |
| Penium brebissonii | Ralfs | image |
| Penium brebissonii var. crassiusculum | (De Bary) Klebs | image |
| Penium brebissonii var. genuinum | Kirchner | image |
| Penium brebissonii var. jenneri | (Ralfs) Kirchner | image |
| Penium brebissonii var. typicum | Klebs | image |
| Penium breve | (Wood) Wille | image |
| Penium breve var. arcticum | Wille | image |
| Penium brevicylindricum | W.M. Kozłowski | Zap. Kievsk. Obshch. Estestvoisp. | 11: 31 | 1890 |
| Penium capitatum | Roll | image |
| Penium chadefaudii | (Bourrelly) Coute | image |
| Penium chodatii var. spinulosum | Bernard | image |
| Penium chodatii_('chodati') | Bernard | image |
| Penium chrysoderma | Borge | image |
| Penium clandestinum | (Kützing) Kützing | image |
| Penium clevei f. elongatum_('elongata') | West & West | image |
| Penium clevei | Lundell | image |
| Penium clevei var. africanum | Schmidle | Bot. Jahrb. | 26: 20, pl. I: fig. 12 | 1898 |
| Penium clevei var. crassum | West & West | image |
| Penium closterioides f. granulatum_('granulata') | Raciborski | image |
| Penium closterioides f. interruptum_('interrupta') | W. West | J. Roy. Micr. Soc. | 1892: 721, no fig. | 1892 |
| Penium closterioides f. minus_('minor') | Heimerl | Ver. Zool.-Bot. Ges. Wien | 41: 590, pl. XXXIV: fig. 4 (in Ralfs) | 1891 |
| Penium closterioides f. punctatum | Raciborski | Rozpr. Wydz. Mat.-Przyr. Akad. Umiej. [Kraków], ser. 2, | 2: 367, pl. VI: fig. 2 | 1892 |
| Penium closterioides f. punctatum_('punctata') | Raciborski | image |
| Penium closterioides | Ralfs | image |
| Penium closterioides var. gracile_('gracilis') | Brühl & Biswas | image |
| Penium closterioides var. minus 'Heimerl' | | image |
| Penium closterioides var. navicula | (Brebisson) Klebs | image |
| Penium closterioides var. spirogranatum | J.A. Cushman | image |
| Penium closterioides var. subcylindricum | Klebs | image |
| Penium closterioides var. tumidum_('tumida') | Istvanffi | image |
| Penium closterioides var. typicum | Klebs | image |
| Penium conspersum var. americanum | Nordstedt | image |
| Penium conspersum var. capense | Fritsch | image |
| Penium conspersum | Wittrock | image |
| Penium costatum | Hodgetts | image |
| Penium crassiusculum | De Bary | Untersuch. Conjugaten: | 73, pl. V: figs. 5-7 | 1858 |
| Penium crassum | (W. West) Irenee-Marie | image |
| Penium crassum f. inflatum_('inflata') | (W. West) Irenee-Marie | image |
| Penium cruciferum | (de Bary) Wittrock in Wittrock & Nordstedt | Alg. Aquae Dulcis Exsicc.: | 482 | 1882 |
| Penium cruciferum var. pluriradians | Wittrock | image |
| Penium cruciferum var. pluriradians | Wittrock | image |
| Penium cucurbitinum | Bisset | image |
| Penium cucurbitinum f. botesii | Claassen | image |
| Penium cucurbitinum f. crassius_('crassior') | Playfair | image |
| Penium cucurbitinum f. majus_('major') | West & West | image |
| Penium cucurbitinum f. minus_('minor') | West & West | image |
| Penium cucurbitinum f. minutissimum | Elenkin | image |
| Penium cucurbitinum f. minutissimum_('minutissima') | Hustedt | image |
| Penium cucurbitinum f. minutum | G.W. Prescott in Prescott & Magnotta | Pap. Michigan Acad. Sci. Arts & Lett. | 20: 158, pl. XXV: fig. 9 | 1935 |
| Penium cucurbitinum var. africanum_('africana') | Cholnoky | image |
| Penium cucurbitinum var. hinganicum | Noda & Skvortzov | image |
| Penium cucurbitinum var. scoticum | (West & West) West & West | image |
| Penium cucurbitinum var. subpolymorphum | Nordstedt | image |
| Penium cucurbitinum var. subpolymorphum | Nordstedt | image |
| Penium curtum | (Brebisson) Kützing | image |
| Penium curtum | (Ralfs) Kützing | Sp. alg.: | 167 | 1849 |
| Penium curtum | Brebisson ex Ralfs | image |
| Penium curtum f. intermedium_('intermedia') | Wille | image |
| Penium curtum f. majus_('major') | Wille | image |
| Penium curtum f. minus_('minor') | Wille | image |
| Penium curtum f. minutum_('minuta') | W. West | image |
| Penium curtum var. globosum | Wille | image |
| Penium curtum var. obtusum | W. West & G.S. West | J. Bot. (London) | 38: 289, pl. 412: figs. 1, 2 | 1900 |
| Penium curtum var. velebiticum | Pevalek | Rad Jugoslavenske akademije znanosti i umjetnosti | 230: 62, fig. 6 | 1925 |
| Penium curtum var. waterbergense | Claassen | image |
| Penium cuticulare | West & G.S. West | J. Roy. Micr. Soc. | 1896: 153, pl. IV: figs. 43, 44 | 1896 |
| Penium cuticulare | West & West | image |
| Penium cylindraceum f. maius | Croasdale | image |
| Penium cylindraceum | K. Förster | Khumbu Himal; Ergebnisse | 2: 33, pl. 1: fig. 13 | 1965 |
| Penium cylindricum | Borge | Ark. Bot. | 1: 75, pl. 1: fig. 5 | 1903 |
| Penium cylindrus | (Ehrenberg) Brebisson | image |
| Penium cylindrus | Brebisson ex Ralfs | image |
| Penium cylindrus f. coloratum_('colorata') | Schmidle | image |
| Penium cylindrus f. majus_('major') | Viret | image |
| Penium cylindrus var. annulatum | Hantzsch | image |
| Penium cylindrus var. attenuatum | Raciborski | image |
| Penium cylindrus var. cuticulare | (West & G.S. West) W. Krieger | Rabenhorst's Krypt.-Fl. Deutschl., 2.Aufl., | 13(1,1): 236 | 1933 |
| Penium cylindrus var. elegans | Viret | image |
| Penium cylindrus var. subtruncatum | Schmidle | image |
| Penium cylindrus var. typicum | Gutwinski | image |
| Penium delicatulum var. minus_('minor') | West & West | image |
| Penium delicatulum var. perforatum | Gutwinski | image |
| Penium delicatulum | W. Joshua | image |
| Penium denticulatum | Irenee-Marie | image |
| Penium diadematum | Gutwinski | image |
| Penium didymocarpum f. majus_('major') | Petkov | image |
| Penium didymocarpum | Lundell | Nova Acta R. Soc. Sci. Upsal., | ser. 3, 8{2}: 85, pl. V: fig. 9 | 1871 |
| Penium didymocarpum var. alpinum | Schmidle | image |
| Penium digitus | (Ehrenberg) Brebisson | image |
| Penium digitus | Brébisson ex Ralfs | Brit. Desmid.: | 150, pl. XXV: fig. 3 | 1848 |
| Penium digitus | Brebisson ex Ralfs | image |
| Penium digitus | Brebisson ex Ralfs | image |
| Penium digitus f. curtum | O. Andersson | Bih. K. Svenska Vet.-Akad. Handl. | 16{Afd. III,5}: 19, fig. 14 | 1890 |
| Penium digitus f. curtum_('curta') | O. Andersson | image |
| Penium digitus f. lamellosum | Steinecke | image |
| Penium digitus f. rectum | W.B. Turner | Alg. Ind. Orient.: | 18, pl. I: fig. 27 | 1893 |
| Penium digitus f. typicum | Steinecke | image |
| Penium digitus f. typicum_('typica') | Steinecke | image |
| Penium digitus var. constrictum | W. West | image |
| Penium digitus var. interruptum | (Brebisson) Klebs | image |
| Penium digitus var. montanum | Lemmermann | image |
| Penium digitus var. typicum | Klebs | image |
| Penium digitus var. ventriosum | Lagerheim | image |
| Penium diplosporum | (Lundell) Jacobsen | image |
| Penium dubium | Noda & Skvortzov | image |
| Penium elegans | Bernard | image |
| Penium exiguum f. largum | J. Sampaio | image |
| Penium exiguum f. latum | J. Sampaio | image |
| Penium exiguum f. lewisii | (W.B. Turner) W. West & G.S. West | image |
| Penium exiguum f. majus_('major') | West & G.S. West | image |
| Penium exiguum var. attenuatum | Gutwinski | image |
| Penium exiguum var. capitatum | (Roll) Kosinskaya | image |
| Penium exiguum var. glaberrimum | Gröndblad | image |
| Penium exiguum var. subrotundatum | W. West | image |
| Penium exiguum | W. West | image |
| Penium fluvii-ganii | Noda & Skvortzov | image |
| Penium foxii | Bernard | image |
| Penium fusiforme | Gay | image |
| Penium gelidum | Wittrock in Nordenskiöld, | Stud. och Forskn.: | 84 adnot, 113 (=table), 122 (=expl. pl.), pl. 3: fig. 24 | 1883 |
| Penium gelidum | Wittrock ex De Toni | image |
| Penium globosum | (Bulnheim) Playfair | Proc. Linn. Soc. N.S.W. | 39: 99, 100 | 1914 |
| Penium globosum f. maximum_('maxima') | Playfair | image |
| Penium globosum var. wollei | (W. West & G.S. West) Playfair | image |
| Penium gonatozygiforme | Claassen | image |
| Penium gracillimum | Playfair | image |
| Penium granulatum | (Benn.) West & West | image |
| Penium granulatum | Brebisson | image |
| Penium granulatum f. minus_('minor') | Wille | image |
| Penium haynaldii | J. Schaarschmidt | Magyar Tud. Akad. Math. Termész. Köz. | 18: 277, fig. 20 | 1883 |
| Penium haynaldii | Schaarschmidt | image |
| Penium haynaldii var. lineare | Boldt | image |
| Penium heimerlianum | Schmidle | Hedwigia | 33: 89 | 1894 |
| Penium heterotaphridium | W. West & G.S. West | Trans. Linn. Soc. London, Bot. | 6: 135, pl. 18: figs. 3, 4 | 1902 |
| Penium heterotaphridium | West & West | image |
| Penium hinganicum | Noda & Skvortzov | image |
| Penium hunanense | Jao | image |
| Penium inconspicuum | W. West & G.S. West | J. Roy. Microscop. Soc. | 1894: 4, pl. I: figs. 6-7 | 1894 |
| Penium inconspicuum | West & West | image |
| Penium incrassatum f. majus_('major') | Maskell | image |
| Penium incrassatum f. minus_('minor') | Maskell | image |
| Penium incrassatum | Maskell | image |
| Penium interruptum | Brebisson ex Ralfs | image |
| Penium interruptum f. minus_('minor') | Borge | Ark. Bot. | 8{13}: 2, fig. 1 | 1909 |
| Penium interruptum var. sectum | W. West | image |
| Penium javanicum | De Wildeman | image |
| Penium jenneri | Ralfs | image |
| Penium jenneri var. garusicum | Cholnoky | image |
| Penium jenneri var. majus_('major') | H. Kufferath | image |
| Penium laeve | (Ralfs) F. Gay | Mon. loc. Conj.: | 71 | 1884 |
| Penium lagenarioides | Roy | image |
| Penium lagenarioides | Roy | image |
| Penium lagenarioides var. intermedium | Gutwinski | image |
| Penium lagenarioides var. sydneyense | Raciborski | image |
| Penium lamellosum | (Brebisson) Brebisson ex Kützing | image |
| Penium lamellosum | Brébisson ex Kützing | Sp. alg.: | 168 | 1849 |
| Penium lamellosum f. giganteum_('gigantea') | Rabenhorst | Algen Sachsens [exsicc.]: | 21/22: 241 | 1852 |
| Penium lamellosum var. minus | Bernard | image |
| Penium lanceolatum var. subcylindricum | West & West | image |
| Penium lanceolatum | W.B. Turner | image |
| Penium latiusculum | (Perty) Perty | image |
| Penium leptodermum | Wittrock | image |
| Penium lewisii | W. Turner | image |
| Penium libellula | (Focke) Nordstedt | image |
| Penium libellula f. interruptum | (W. West) W. West & G.S. West | J. Roy. Micr. Soc. | 1897: 479 | 1897 |
| Penium libellula f. majus_('major') | Borge | image |
| Penium libellula f. minus_('minor') | Nordstedt | image |
| Penium libellula var. asiaticum | Skvortzov & Noda | image |
| Penium libellula var. intermedium | Roy & Bisset | image |
| Penium libellula var. interruptum | (W. West) W. West & G.S. West | A monograph of the British Desmidiaceae | 1: 74 | 1904 |
| Penium libellula var. schweickerdtii | Claassen | image |
| Penium magellanicum | Borge | image |
| Penium margaritaceum | (Ehrenberg) Brebisson | image |
| Penium margaritaceum | Brébisson ex Ralfs | image |
| Penium margaritaceum f. elongatum | (Klebs) Kossinskaya | image |
| Penium margaritaceum f. glabrum_('glabra') | Messikommer | image |
| Penium margaritaceum f. longius_('longior') | Raciborski | image |
| Penium margaritaceum f. longum_('longa') | Huber-Pestalozzi | image |
| Penium margaritaceum f. majus_('major') | Irenee-Marie | image |
| Penium margaritaceum f. minus_('minor') | Cedergren | image |
| Penium margaritaceum f. spirale_('spiralis') | Nordstedt | image |
| Penium margaritaceum f. subspiniferum_('subspinifera') | Woodhead & Tweed | North Western Naturalist | 23: 24, fig. 10 | 1948 |
| Penium margaritaceum var. annulare | Hinode | image |
| Penium margaritaceum var. brevius_('brevior') | Claassen | image |
| Penium margaritaceum var. cylindrus | (Ehrenberg) Klebs | image |
| Penium margaritaceum var. elongatum | Gaidukov | image |
| Penium margaritaceum var. elongatum | Klebs | image |
| Penium margaritaceum var. incognitum | Claassen | image |
| Penium margaritaceum var. indivisum | Playfair | image |
| Penium margaritaceum var. irregularius | West & West | image |
| Penium margaritaceum var. obesum | Cushman | image |
| Penium margaritaceum var. papilliferum | R.M. Whelden | image |
| Penium margaritaceum var. pulverulentulum | Playfair | image |
| Penium margaritaceum var. punctatum | Ralfs | image |
| Penium margaritaceum var. typicum | Klebs | image |
| Penium maximum | Schmidle | image |
| Penium maximum | Schmidle | Österr. Bot. Z. | 49: 1 | 1899 |
| Penium mesianum | Claassen | image |
| Penium minimum | Senkt | image |
| Penium minutissimum f. majus_('major') | Wille | image |
| Penium minutissimum | Nordstedt | Lunds Univ. A\*orsskr. | 9(Afd. II, Nr. 10): 46, pl.: fig. 2 | 1873 |
| Penium minutissimum var. gracile | Auclair | image |
| Penium minutum | (Ralfs) Cleve | image |
| Penium minutum f. genuina | Raciborski | image |
| Penium minutum f. inflatum_('inflata') | W. West | image |
| Penium minutum f. majus_('major') | Lundell | image |
| Penium minutum f. punctatum_('punctata') | W. West | image |
| Penium minutum var. alpinum | Raciborski | image |
| Penium minutum var. crassum | W. West | image |
| Penium minutum var. elongatum | (West) West & West | image |
| Penium minutum var. genuinum | Raciborski | image |
| Penium minutum var. gracile | Wille | Forh. Vidensk.-Selsk. Christiania | 1880{11}: 51, pl. II: fig. 33 | 1880 |
| Penium minutum var. lineare | (Kützing) Rabenhorst | image |
| Penium minutum var. minus_('minor') | Raciborski | image |
| Penium minutum var. polonicum | (Raciborski) W. West | image |
| Penium minutum var. productum | Fritsch | image |
| Penium minutum var. tumidum | Wille | image |
| Penium minutum var. undulatum | W. West | J. Linn. Soc., London. Botany | 29: 130, pl. XX: fig. 4 | 1892 |
| Penium monile | (Kützing) Brebisson ex Kützing | image |
| Penium mooreanum var. constrictum | Schmidle | image |
| Penium mooreanum var. constrictum_('constricta') | Schmidle | image |
| Penium mooreanum | W. Archer | image |
| Penium multicostatum | Scott & Gröndblad | image |
| Penium naegelii | Brébisson apud Archer in Pritchard | Hist. Inf. ed. 4: | 751 | 1861 |
| Penium naegelii | Brebisson | image |
| Penium naegelii f. majus_('major') | Nordstedt | image |
| Penium naegelii f. minus_('minor') | Nordstedt | image |
| Penium navicula | Brebisson | image |
| Penium navicula f. granulatum_('granulata') | W. West & G.S. West | image |
| Penium navicula f. maius_('maior') | Borzecki | image |
| Penium navicula f. maius_('maior') | Borzecki | image |
| Penium navicula f. majus_('major') | Huber-Pestalozzi | image |
| Penium navicula f. willei | Schmidle | image |
| Penium navicula var. attenuatum | Noda & Skvortzov | image |
| Penium navicula var. crassum | West & West | image |
| Penium navicula var. granulatum | West & G.S. West | J. Linn. Soc., London. Botany | 33: 157, pl. 8: fig. 10 | 1897 |
| Penium navicula var. inflatum | W. West & G.S. West | Monogr. Brit. Desmid. | I: 77, pl. VII: fig. 18 | 1904 |
| Penium navicula var. inflatum | West & West | image |
| Penium navicula var. maximum | Bernard | image |
| Penium navigium | W.B. Turner | image |
| Penium notabile | (Brébisson) F. Gay | Mon. loc. Conj.: | 71 | 1884 |
| Penium notabile f. latius | F. Gay | Mon. loc. Conj.: | 71, no fig. | 1884 |
| Penium oblongum | De Bary | image |
| Penium oblongum f. majus | W.B. Turner | Alg. Ind. orient.: | 18, pl. I: fig. 22 | 1893 |
| Penium oblongum f. majus_('major') | W.B. Turner | image |
| Penium orbiculatum | (Ralfs) Kützing | image |
| Penium pachydermum | Playfair | image |
| Penium palangula | Brebisson | image |
| Penium palangula var. debaryi | (Rabenhorst) F. Gay | Mon. loc. Conj.: | 71 | 1884 |
| Penium pandurans | De Notaris | image |
| Penium phymatosporum f. minus | K. Förster | Khumbu Himal; Ergebnisse | 2: 33, pl. 1: figs. 15, 16; pl. 6: fig. 5 | 1965 |
| Penium phymatosporum | Nordstedt | image |
| Penium phymatosporum var. crassulum | Cholnoky | image |
| Penium phymatosporum var. majus | Wittrock & Nordstedt | image |
| Penium phymatosporum var. pachydermum | Printz | image |
| Penium poeltianum | K. Förster | Khumbu Himal; Ergebnisse | 2: 34, pl. 1: figs. 7-9; pl. 6: figs. 2-4 | 1965 |
| Penium polonicum | Raciborski | image |
| Penium polymorphum | (Perty) Perty | image |
| Penium polymorphum f. alpicola | Heimerl | image |
| Penium polymorphum f. angustius | Gröndblad | image |
| Penium polymorphum f. obesum | W.B. Turner | image |
| Penium polymorphum var. cylindraceum | Playfair | image |
| Penium polymorphum var. discrepans | Kaiser | image |
| Penium polymorphum var. longius | Bohlin | image |
| Penium polymorphum var. lundellii | Schmidle | image |
| Penium polymorphum var. minutissimum | (Nordstedt) Playfair | image |
| Penium polymorphum var. mooreanum | (Archer) Playfair | image |
| Penium polymorphum var. rectum | Gröndblad | image |
| Penium polymorphum var. turneri | Playfair | Proc. Linn. Soc. New South Wales | 37: 527 | 1913 |
| Penium pseudocostatum | Suxena & Venkateswarlu | image |
| Penium pseudorufescens | Claassen | image |
| Penium pusillum | Delponte | image |
| Penium pyramidatam | (West & West) Krieger | image |
| Penium ralfsii | DeBary | image |
| Penium ralfsii | Kützing | Sp. alg.: | 167 | 1849 |
| Penium ralfsii | Kützing | image |
| Penium rectum | (Delponte) Wille | image |
| Penium rectum f. minus_('minor') | Wille | image |
| Penium ridleyi | Bernard | image |
| Penium rotundum | W.B. Turner | image |
| Penium royanum | W.B. Turner | image |
| Penium rufescens | Cleve | image |
| Penium rufescens f. achroa | Messikommer | image |
| Penium rufescens f. longius | Kosinskaya | image |
| Penium rufo-pellitum | J. Ray | image |
| Penium rupestre | (Kützing) Rabenhorst | Fl. Eur. Alg. III: | 120 | 1868 |
| Penium rupestre | (Kützing) Rabenhorst | image |
| Penium scandinavicum | W.B. Turner | image |
| Penium sceptrum | Borge | image |
| Penium sibiricum | Boldt | image |
| Penium silvae-nigrae f. minus | C. Bicudo | image |
| Penium silvae-nigrae f. minus_('minor') | Bourrelly | image |
| Penium silvae-nigrae var. parallelum | W. Krieger | Rabenhorst's Krypt.-Fl. Deutschl., 2.Aufl., | 13(1,1): 240, pl. 11: fig. 5 | 1933 |
| Penium silvae-nigrae_('silvae nigrae') | Rabanus | image |
| Penium simplex | W.B. Turner | image |
| Penium sinense | Jao | image |
| Penium spinospermum | W. Joshua | image |
| Penium spinulosum | (Wolle) Gerrath | image |
| Penium spinulosum var. madagascariense | (Brunel) Gerrath | image |
| Penium spiroplastidium | G.W. Prescott in Prescott, Croasdale & Vinyard | Syn. N. Amer. Desmids | II{1}: 13, pl. IX: fig. 8 | 1975 |
| Penium spirostriolatiforme f. rectispirum | (Grönblad) H. Croasdale in Croasdale & Scott, | Nova Hedwigia | 27: 506 | 1976 |
| Penium spirostriolatiforme f. rectispirum | (Gröndblad) Croasdale | image |
| Penium spirostriolatiforme | West & West | image |
| Penium spirostriolatum f. elongatum | Thomasson | image |
| Penium spirostriolatum f. interruptum_('interrupta') | Cedergren | image |
| Penium spirostriolatum f. rectispirum | Grönblad | Acta Soc. Sci. Fenn. n.s.B, | 2{6}: 8, fig. 6 | 1945 |
| Penium spirostriolatum f. rectispirum_('rectispira') | Gröndblad | image |
| Penium spirostriolatum f. scabrum_('scabra') | Eichler | Pamietnik Fizyjograficzny | 14{Dzial 3}: 125, fig. 10 | 1896 |
| Penium spirostriolatum | J. Barker | image |
| Penium spirostriolatum var. amplificatum | Max Schmidt | Grundlagen einer Algenflora der Lüneburger Heide: | 16, pl. II: fig. 19 | 1903 |
| Penium spirostriolatum var. apiculatum | J.A. Cushman | image |
| Penium spirostriolatum var. minus_('minor') | Rabanus | image |
| Penium spirostriolatum var. pseudosilvae-nigrae | Förster | image |
| Penium striato-punctatum | Kützing | image |
| Penium subcucurbitinum | Claassen | image |
| Penium sublamellosum | W.B. Turner | image |
| Penium suboctangulare | W. West | image |
| Penium subrufescens | Borge | image |
| Penium subspirostriolatiforme | Grönblad | image |
| Penium substriatum | Hirano | image |
| Penium subtile | West & West | image |
| Penium subtruncatum | (Schmidle) Schmidle | image |
| Penium teres | G. Sampaio | image |
| Penium terrestre | Jao | image |
| Penium tridentulum | (Wolle) Eichler & Raciborski | image |
| Penium truncatum f. punctatum_('punctata') | W. West | image |
| Penium truncatum | Ralfs | image |
| Penium variolatum | W. West & G.S. West | image |
| Penium variolatum | West & G.S. West | J. Bot. (London) | 35: 77, pl. 368: fig. 23 | 1897 |
| SPHINCTOPENIUM | (Gay) W.B. Turner | image |
| SPHINCTOPENIUM | Gay | image |