Belongs within: Lycophytina.
Contains: Selaginella, Lepidocarpales.
The Isoetophyta include the modern quillworts (Isoetes) and spikemosses (Selaginella). Modern species are small herbaceous plants though the Palaeozoic Lepidocarpes included large arborescent forms. Isoetophytes possess a ligule, and members of the crown group Isoetopsida are heterosporous (Doyle 1998). The Devonian to Early Permian Protolepidodendrales exhibited forked microphylls (Crane & Kendrick 1997). Isoetes species are aquatic or grow in wet ground, and have crowded quill-like leaves arising from a short central axis (Allan 1961).
<==Isoetophyta [Ligulateae]
|--ProtolepidodendralesSP12
| | i. s.: Acinosporites lindlarensis Richardson et al. 1993SP12
| | Leclercqia Banks et al. 1972CD07, SP12
| | `--L. complexaBC98
| | Minarodendron cathaysiensisCK97
| |--Eleutherophyllum [Eleutherophyllaceae]C93
| | |--E. hamatum Josten 1983C93
| | `--E. waldenburgense (Stur) Zimmermann 1930C93
| `--ProtolepidodendraceaeC93
| |--Sugambrophyton pilgeri Schmidt 1954C93
| |--Brasilodendron pedroanum Chaloner et al. 1979C93
| `--ProtolepidodendronS00
| |--P. scharianumS00
| `--P. yalwalenseY99
`--Isoetopsida [Glossopsida, Heterosporales]CD07
|--Selaginellaceae [Selaginellales]C93
| |--SelaginellaCD07
| `--Barsostrobus famennensis Fairon-Demaret 1977C93
`--+--LepidocarpalesD98
`--IsoetalesC93
| i. s.: Takhtajanodoxa [Takhtajanodoxaceae]C93
| `--T. mriabilis Snigirevskaya 1980C93
| Paralycopodites pulcherrimaCK97
|--ChaloneriaceaeC93
| |--Chaloneria cormosa Pigg & Rothwell 1983D98, C93
| `--Polysporia mirabilis Newberry 1873C93 [incl. Lepidostrobus zea Chaloner 1953P63]
`--+--PleuromeiaceaeC93
| |--Pleuromeia jiaochengensis Wang & Wang 1982D98, C93
| `--Annalepsis zeilleri Fliche 1905C93
`--IsoetaceaeC93
|--Bothrodendrostrobus mundus Hirmer 1927C93
`--Isoetes Linnaeus 1753CD07, A61
|--I. alpinus Kirk 1875 [incl. I. multiangularis Col. 1890]A61
|--I. andicolaR02
|--I. andinaR02
|--I. bolanderi [incl. I. bolanderi var. pygmaea]H93
|--I. capensisRHS09
|--I. colamandrina Linnaeus 1781I88
|--I. coromandelinaLK14
| |--I. c. ssp. coromandelinaLK14
| `--I. c. ssp. macrotuberculataLK14
|--I. drummondii Br. 1863 [incl. I. phoeospora, I. tripus Br. 1863]B78
|--I. echinospora [incl. I. braunii, I. muricata]H93
|--I. eludens Roux, Hopper & Smith 2009RHS09
|--I. engelmanniiCK97
|--I. flaccidaSL05
|--I. histrixY98
|--I. howellii [incl. I. howellii var. minim]H93
|--I. kirkii Braun 1869A61
|--I. lacustris Linnaeus 1753CD07 (see below for synonymy)
|--I. muelleriLK14
|--I. muricataM68
| |--I. m. var. muricataM68
| `--I. m. var. hesperia [=I. echinosperma var. hesperia]M68
|--I. nuttalliiH93
|--I. occidentalis [incl. I. lacustris var. paupercula]H93
|--I. orcuttiiH93
|--I. savatieriM03
|--I. tegetiformansWZ22
|--I. toximontanaRHS09
`--I. triquetraR02
Isoetes lacustris Linnaeus 1753CD07 [incl. I. elatiorB78, I. gunnii Br. 1868B78, I. hookeri Br. 1868B78, I. humiliorB78, I. stuartii Br. 1868B78, I. tasmanicaB78]
*Type species of generic name indicated
References
[A61] Allan, H. H. 1961. Flora of New Zealand vol. 1. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. R. E. Owen, Government Printer: Wellington (New Zealand).
[BC98] Bateman, R. M., P. R. Crane, W. A. DiMichele, P. R. Kenrick, N. P. Rowe, T. Speck & W. E. Stein. 1998. Early evolution of land plants: phylogeny, physiology, and ecology of the primary terrestrial radiation. Annual Review of Ecology and Systematics 29: 263–292.
[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.
[CD07] Cantino, P. D., J. A. Doyle, S. W. Graham, W. S. Judd, R. G. Olmstead, D. E. Soltis, P. S. Soltis & M. J. Donoghue. 2007. Towards a phylogenetic nomenclature of Tracheophyta. Taxon 56 (3): E1–E44.
[C93] Cleal, C. J. 1993. Pteridophyta. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 779–794. Chapman & Hall: London.
[CK97] Crane, P. R., & P. Kenrick. 1997. Problems in cladistic classification: higher-level relationships in land plants. Aliso 15 (2): 87–104.
[D98] Doyle, J. A. 1998. Phylogeny of vascular plants. Annual Review of Ecology and Systematics 29: 567–599.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[I88] Iwatsuki, K. 1988. An enumeration of the pteridophytes of Nepal. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 231–339.
[LK14] Lyons, M. N., G. J. Keighery, L. A. Gibson & T. Handasyde. 2014. Flora and vegetation communities of selected islands off the Kimberley coast of Western Australia. Records of the Western Australian Museum Supplement 81: 205–244.
[M03] Macloskie, G. 1903. Pteridophyta, ferns and fernlike plants. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 127–138. The University: Princeton (New Jersey).
[M68] Munz, P. A. 1968. Supplement to a California Flora. University of California Press.
[P63] Playford, G. 1963. Lower Carboniferous microfloras of Spitsbergen. Part two. Palaeontology 5 (4): 619–678.
[R02] Raven, J. A. 2002. Selection pressures on stomatal evolution. New Phytologist 153: 371–386.
[RHS09] Roux, J. P., S. D. Hopper & R. J. Smith. 2009. Isoetes eludens (Isoetaceae), a new endemic species from the Kamiesberg, Northern Cape, South Africa. Kew Bulletin 64 (1): 123–128.
[S00] Schweitzer, H. J. 2000. Neue Pflanzenfunde im Unterdevon der Eifel (Deutschland). Senckenbergiana Lethaea 80 (2): 371–395.
[SL05] Small, R. L., E. B. Lickey, J. Shaw & W. D. Hauk. 2005. Amplification of noncoding chloroplast DNA for phylogenetic studies in lycophytes and monilophytes with a comparative example of relative phylogenetic utility from Ophioglossaceae. Molecular Phylogenetics and Evolution 36: 509–522.
[SP12] Steemans, P., E. Petus, P. Breuer, P. Mauller-Mendlowicz & P. Gerrienne. 2012. Palaeozoic innovations in the micro- and megafossil plant record: from the earliest plant spores to the earliest seeds. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 437–477. Springer.
[WZ22] Wang, Q.-H., J. Zhang, Y. Liu, Y. Jia, Y.-N. Jiao, B. Xu & Z.-D. Chen. 2022. Diversity, phylogeny, and adaptation of bryophytes: insights from genomic and transcriptomic data. Journal of experimental Botany 73 (13): 4306–4322.
[Y98] Yannitsaros, A. 1998. Additions to the flora of Kithira (Greece) I. Willdenowia 28: 77–94.
[Y99] Young, G. C. 1999. Preliminary report on the biostratigraphy of new placoderm discoveries in the Hervey Group (Upper Devonian) of central New South Wales. Records of the Western Australian Museum Supplement 57: 139–150.