Isoetes multiangularis Colenso
Vascular – Native
Lycophytes (clubmosses, selaginella, quillworts)
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
2n = 22
Current conservation status
The threat classification status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – a suggested threat classification status has not been assessed by the NZTCS panel.
2017 | At Risk – Declining | Qualifiers: RR
Previous conservation statuses
2012 | At Risk – Declining | Qualifiers: RR
2009 | Not Threatened
2004 | Not Threatened
Endemic. New Zealand: North and South Islands from the upper Waikato River (near Whakamaru) and Rotorua Lakes south to Otago and northern Southland. Historically present in Northland at Lake Omapere and along the Wairua River, and in the lower Waikato at lakes Whangape, Waikare and Waahi.
Lowland and montane, aquatic (rarely subterrestrial) at the bottom of lakes, rivers and streams (rarely growing near shoreline where it may be partially exposed during low water levels). Often forming extensive colonies in fine sediments or coarse sand.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland).
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Aquatic, heterosporous, tufted herb arising from an erect corm. Roots long and stout, dichotomously branched. Leaves mostly sporophyllous, rather brittle, spirally (rarely flabellately) arranged, erect in tufts of up to 30, dark green to yellow-green, usually evenly septate, septae forming air chambers; lamina 30-150(-240) mm long,filiform to linear-filiform, tapered to an finely acute (rarely subacute to obtuse) apex, base swollen, up to 5 mm wide. Leaf appendages ligulate, ligule broadly triangular 0.8-1.2 mm long, located above the sporangium on the adaxial side. Sporangia adaxially located in pockets in leaf bases, large (up to 3 mm long) and conspicuous, broadly oblong, heterosporous, Megaspores white, studded with conspicuous, minute, unequal tubercles; microspores minute, numerous.
New Zealand Isoetes are in serious need of a thorough revision. As currently circumscribed the two species I. alpina and I. kirkii significantly overlap in most features except the megaspore surface which in I. kirkii is finely though conspicuously tubercled, while it is usually smooth in I. alpina. The megaspores of I. kirkii are also usually white, whilst those of I. alpine are typically grey to greyish white.A potentially distinct form with a taller (up to 240 mm long), finer filiform, flabellately arranged rather than spirally arranged leaves was known from several sites in Northland. This race is included in the above description of I. kirkii. It is now believed to be extinct in the wild, though it is known from cultivated material that was rescued from the last known habit. The race may be worth of formal taxonomic recognition (see comments in de Lange & Rolfe 2010). This race is treated as Isoetes aff. kirkii (CHR 247118A; Lake Omapere) in de Lange et al. 2009.
N.A. Spore producing
N.A. Spore producing
Spongy megaspores are dispersed by water
Easily grown in a fish tank ot fish pond planted in a coarse mix of sand and peat. Algal blooms area problem. Plants are very slow growing
isoetes: From the Greek isos ‘equal’ and etas ‘year’, referring to the evergreen, unchanging character of the plant (Johnson and Smith, 1986).
kirkii: After Thomas Kirk (18 January 1828 - 8 March 1898), a NZ botanist and lecturer in natural sciences and regarded as a leader of botanical enquiry in NZ for over three decades. One of his most significant publications was Forest flora of NZ (1889) but he also contributed over 130 papers to the Transactions and Proceedings of the NZ Institute and other journals.
Where To Buy
Not commercially available.
Fact sheet including description prepared for NZPCN by P.J. de Lange (7 May 2011)
References and further reading
de Lange, P.J.; Rolfe, J.R. 2010: New Zealand Indigenous Vascular Plant Checklist 2010. Wellington, New Zealand Plant Conservation Network.
de Lange, P.J.; Norton, D.A.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Hitchmough, R.; Townsend, A.J. 2009: Threatened and uncommon plants of New Zealand (2008 revision). New Zealand Journal of Botany 47: 61-96.
Johnson, A. T. and Smith, H. A (1986). Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd: Buckenhill, UK.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Isoetes kirkii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/isoetes-kirkii/ (Date website was queried)