Isoetes lacustris

Isoetes lacustris

Taxonavigation

Taxonavigation: Isoetales
Superregnum: Eukaryota Cladus: Diaphoretickes Cladus: CAM Cladus: Archaeplastida Regnum: Plantae Divisio: Tracheophyta Divisio: Lycopodiophyta Classis: Lycopodiopsida Subclassis: Isoetidae Ordo: Isoetales

Familia: Isoetaceae
Genus: Isoetes
Species: Isoetes lacustris

Name

Isoetes lacustris L., Sp. Pl. 2: 1100 (1753).

• Type locality according to protologue: “in Europae frigidae fundo lacuum”.
• Lectotype (designated by Fuchs in Beih. Nova Hedwigia 3: 30, 103, fig. 10. 1962): Herb. Linn. 1256.1 (LINN).

Synonyms

• Homotypic
  • Isoetes lacustris subsp. eu-lacustris Syme, Engl. Bot. ed. 3 12: 4 (1886), nom. inval.
  • Isoetes lacustris var. genuina Syme, Engl. Bot. ed. 3 12: 5 (1886), nom. inval.
  • Calamaria lacustris (L.) Kuntze, Rev. Gen. Pl. 2: 828 (1891)
• Heterotypic
  • Isoetes setacea Lam., Encycl. 3: 314 (1789). [accepted by POWO]
    • Lectotype (designated by Fuchs in Beih. Nova Hedwigia 3: 30, 103, fig. 10. 1962): “Se trouve dans les eaux du lac de St-Andéol, sur les montagnes d’Aubrac, en Gevaudan. L’eau surmonte la plante de 3 ou 4 pieds, ex D. Bonnaterre, 1789” (P-LA P00565109, excluding the scanning micrographs of spores, added later).
    • Calamaria setacea (Lam.) Kuntze, Rev. Gen. Pl. 2: 828 (1891).
  • Isoetes lacustris var. fragilis Gray, Nat. Arr. Brit. Pl. 2: 24 (1821 publ. 1822).
  • Isoetes lacustris var. gracilis Gray, Nat. Arr. Brit. Pl. 2: 24 (1821 publ. 1822).
  • Isoetes lacustris var. crassa Léman in F. Cuvier, Dict. Sci. Nat., ed. 2, 24: 24 (1822).
  • Isoetes lacustris var. setacea Léman in F. Cuvier, Dict. Sci. Nat., ed. 2, 24: 24 (1822).
  • Isoetes lacustris var. tenella Léman in F. Cuvier, Dict. Sci. Nat., ed. 2, 24: 24 (1822) (as “Isoetes lacustris … variété isoetes tenella”, see ICN Art. 24.4)
    • Lectotype (designated by Fuchs in Beih. Nova Hedwigia 3: 54, 103, fig. 12. 1962): [Illustration] “Flora Danica Tab. CXCI” in Oeder, Fl. Dan.: t. 191. 1765.
    • Epitype (designated by Greuter & Troìa 2015: 813): “Norwegen: Valasjöen zw. Dombas und Hjerkin (Dovre), 936 m NN”, 13.10.1972, Hinz s.n. (B 20 136040).
    • Isoetes tenella (Léman) Desv., Mém. Soc. Linn. Paris 6: 179 (1827).
  • Isoetes lacustris var. stricta J.Gay, Bull. Soc. Bot. France 10: 392 (1863), nom. nud., "strictum"
    • Isoetes lacustris var. stricta J.Gay ex Mer, Bull. Soc. Bot. France 28: 72 (1881).
    • Isoetes lacustris var. stricta J.Gay ex Motelay & Vendryès, Actes Soc. Linn. Bordeaux 36: 327 (1883), isonym
  • Isoetes lacustris var. minor Milde, Höh. Sporenpfl. Deutschl. 141 (1865).
  • Isoetes lacustris var. tenuifolia A.Braun ex Milde, Höh. Sporenpfl. Deutschl. 141 (1865).
  • Isoetes atrovirens Th.Fr., Bot. Notis. 1865: 48 (1865).
  • Isoetes lacustris var. elatior Fliche, Les Isoetes des Vosges: 7 (1879).
  • Isoetes lacustris var. falcata Gay, Bull. Soc. Bot. France 10: 386 (1863), nom. nud., Fliche, Les Isoetes des Vosges: 7 (1879).
    • Type locality: United Kingdom, Wales, Lake Dwythwch, August 1862, C. Gay
  • Isoetes morei D.Moore, J. Bot. 16: 353, t. 199 (1878).
    • Isoetes lacustris var. morei (D.Moore) Hook.f., Student's Fl. Brit. Isl., ed. 3, 526 (1884).
    • Isoetes lacustris var. morei (D.Moore) Syme & N.E.Br., Engl. Bot., ed. 3B, 12: 5 (1886), isonym
  • Isoetes lacustris var. humilis Mer, Bull. Soc. Bot. France 28: 72 (1881).
    • Type locality: France, Dép. Vosges, Lac de Longemer
  • Isoetes lacustris var. intermedia Mer, Bull. Soc. Bot. France 28: 72 (1881).
    • Type locality: France, Dép. Vosges, Lac de Longemer
  • Isoetes lacustris var. humilior Motelay & Vendryès, Actes Soc. Linn. Bord. 36: 327 (1883), nom. nud.
  • Isoetes lacustris var. terrestris Motelay & Vendryès, Actes Soc. Linn. Bord. 36: 327 (1883).
  • Isoetes lacustris var. leiospora H.Klinggr., Schrift. Naturf. Ges. Danzig 6(1): 20 (1884).
    • Type locality: Poland, Pomerania, Großer Ottalsiner See, 1882, Klinggraeff & Lützow
  • Isoetes lacustris var. vulgaris Casp. in Luerss., Farnpfl. 855 (1889).
  • Isoetes lacustris subsp. abbreviata Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. arvernensis Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. cambrica Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. curvifolia Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
    • Isoetes lacustris var. curvifolia Casp. in in C.M.H. Glück & A.A. Pascher, Süsswasserflora 15: 10 (1936).
  • Isoetes lacustris subsp. editorum Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. errabunda Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. lamottei Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. langei Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. latifolia Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. noltei Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. obscura Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. pervaga Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. rivalis Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. rossica Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. scanica Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. scotica Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. septentrionalis Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. spreta Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. succedanea Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. suecica Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris subsp. vergens Gand., Fl. Eur. 27: 193 (1891), opus utiq. oppr.
  • Isoetes lacustris var. recurva Motelay & Vendryès, Actes Soc. Linn. Bord. 36: 327 (1883), nom. nud.
  • Isoetes lacustris var. rectifolia Casp. in C.M.H. Glück & A.A. Pascher, Süsswasserflora 15: 10 (1936).

Hybrids

I. × brochonii

Distribution

Native distribution areas:

Continental: Europe Regional: Northern Europe Denmark, Finland, Føroyar, Great Britain, Iceland, Ireland (Eire, Northern Ireland), Norway, Sweden. Regional: Middle Europe Austria (in error), Czechia-Slovakia (Czechia), Germany, Netherlands, Poland, Switzerland. Regional: Southwestern Europe France, Spain (Andorra, Spain). Regional: Southeastern Europe Bulgaria, Greece (in error), Italy (in error), Romania (doubtfully present), Northwest Balkan Peninsula (North Macedonia). Regional: Eastern Europe Belarus, Baltic States (Estonia, Latvia, Lithuania), North European Russia, Northwest European Russia. Continental: Asia-Temperate Regional: Siberia Altay, Irkutsk, West Siberia. Regional: Eastern Asia Japan (doubtfully present). Continental: Northern America Regional: Subarctic America Greenland. References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition

References

Primary references

• Linnaeus, C. 1753. Species Plantarum. Tomus II: 1100. Reference page. 

Additional references

• Pfeiffer, N.E. 1922. Monograph of the Isoetaceae. Annals of the Missouri Botanical Garden 9(2): 79–218, pls. xii–xix. JSTOR, BHL Reference page. 
• Greuter, W. & Troìa, A. 2015. Disentangling Isoetes setacea and removing threats to Isoetes echinospora. Taxon 64(4): 811–815. DOI: 10.12705/644.12 Reference page. 
• Prellp, R. & Bock, C. 1989. Isoetes brochonii Motelay: une nouvelle interprétation. Bulletin de la Société Botanique de France. Lettres Botaniques 136(2): 137–150, DOI: 10.1080/01811797.1989.10824835 Reference page.  (relegating Isoetes brochonii to the synonymy of Isoetes lacustris)
• Troìa, A., Pereira, J.B.S., Kim, C. & Taylor, W.C. 2016. The genus Isoetes (Isoetaceae): a provisional checklist of the accepted and unresolved taxa. Phytotaxa 277(2): 101–145. DOI: 10.11646/phytotaxa.277.2.1 ResearchGate Reference page. 
• Brunton, D.F., Sokoloff, P.C. & Aymerich, P. 2020. The taxonomy, status and origin of Isoetes ×brochonii and I. creussensis (Isoetaceae), two Pyrenean endemic taxa. Botany Letters 167(4): 391–408. DOI: /10.1080/23818107.2020.1790034 Reference page. 

Links

• Hassler, M. 2026. World Ferns. Checklist of Ferns and Lycophytes of the World. . Isoetes lacustris Accessed: 23 May 2026. Reference page.
• Tela Botanica (ed.) 2000 onwards: Tela Botanica. Le réseau de la botanique francophone. eFlore. Isoetes lacustris. Association Tela Botanica, Montpellier, France. Accessed: 2018 July 11.
• Hand, R., Thieme, M. & collaborators 2025. Florenliste von Deutschland – Gefäßpflanzen, Version 15. May 2025. Founded by Karl Peter Buttler, published on the internet (https://www.florenliste-deutschland.de). Reference page. 

Vernacular names

• dansk: Sortgrøn Brasenføde
• Deutsch: See-Brachsenkraut
• English: Lake quillwort
• eesti: Järv-lahnarohi
• suomi: Tummalahnanruoho
• français: Isoète lacustre
• polski: Poryblin jeziorny
• русский: Полушник озёрный

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