Classification
 Nomenclature
Scientific Name:
Thelypteris confluens (Thunb.) C.V.Morton, Contr. U.S. Natl. Herb. 38: 71 (1967)
Synonymy:
  • Pteris confluens Thunb., Prodr. Pl. Cap. 171 (1800)
Holotype: e Cap b. Spei [Cape of Good Hope, South Africa], C.P.Thunberg s.n., UPS–T 24904 (n.v., see Roux 2009)
  • = Aspidium thelypteris var. squamigerum Schltdl., Adumbr. Fil. 23, t. 11 (1825)
  • Aspidium squamigerum (Schltdl.) Fée, Mém. Foug., 8. Descr. Esp. Nouv. 104 (1857)
  • Thelypteris palustris var. squamigera (Schltdl.) Weath. in Johnston, Contr. Gray Herb. 73: 40 (1924)
  • Thelypteris squamigera (Schltdl.) Ching, Bull. Fan Mem. Inst. Biol. 6: 329 (1936) – as squamulosa
Holotype: atque in Promontorio bonae spei ad Hexriver [Hex River, Cape of Good Hope, South Africa], J.L.L.Mund et L. Maire, C.H. Bergius s.n., P 00482788 (!online)
  • = Nephrodium squamulosum Hook.f., Bot. Antarct. Voy. II (Fl. Nov.-Zel.) Part II, 39 (1854)
  • Nephrodium thelypteris var. squamulosum (Hook.f.) Hook., Sp. Fil. 4, 88 (1862)
  • Dryopteris thelypteris var. squamulosum (Hook.f.) Cheeseman, Man. New Zealand Fl., ed. 2, 33 (1925)
Lectotype (chosen by Holttum 1977): New Zealand, Colenso, K! (photo WELT E471/13)
  • = Lastrea invisa J.B.Armstr., Trans. & Proc. New Zealand Inst. 13: 359 (1881)
Holotype: Waikato, Herb. Armstrong, CHR 633400!
Etymology:
From the Latin confluens (running together).
Vernacular Name(s):
marsh fern; swamp fern; swamp lady fern
 Description

Rhizomes long-creeping, up to 175 mm long (in herbarium specimens) with stipes arising 8–37 mm apart, 1.5–3 mm diameter, bearing scattered scales. Rhizome scales ovate to broadly ovate, 1–3 mm long, 0.5–1.5 mm wide, pale brown, entire.  Fronds 380–1150 mm long, held stiffly upright. Stipes 180–670 mm long, yellow-brown to chestnut-brown and often almost black at the base, glabrous or scaly near base, slightly polished. Laminae sometimes appearing slightly dimorphic with fertile pinna segments inrolled and a little narrower than the sterile, deeply 1-pinnate-pinnatifid to 1-pinnate-pinnatisect, narrowly elliptic to elliptic, or rarely narrowly obovate, usually narrowed to a short pinnatifid apex, 150–540 mm long,  40–145 mm wide, mid-green on both surfaces, herbaceous to coriaceous. Broadly ovate or broadly elliptic or almost orbicular pale brown scales on abaxial surface of pinna midribs and costae; colourless, acicular and capitate hairs up to 1 mm long on both surfaces of costae and veins. Primary pinnae in 14–27 pairs below pinnatifid apex, widely spaced especially proximally, narrowly elliptic or narrowly ovate to almost oblong; the longest at about mid-lamina, short-stalked, 25–80 mm long, 6–18 mm wide; the basal pair not or scarcely reduced in length. Primary pinnae divided almost, or rarely completely, to the midrib; ultimate segments oblong, 3–10 mm long, 1.5–3 mm wide, apices acute to obtuse, margins usually inrolled, bases adnate to decurrent. Veins all free, forking in sterile pinna segments, undivided in fertile segments. Sori round, in one row either side of midrib away from pinna margins; indusia reniform, 0.4–0.6 mm diameter, bearing capitate hairs.

 Recognition

Thelypteris confluens is recognised by its long-creeping rhizomes, rigidly erect fronds, deeply 1-pinnate-pinnatifid to 1-pinnate-pinnatisect laminae, pinnae divided almost to the midribs, basal pair of pinnae not reduced in length, free veins, indumentum on the abaxial surfaces comprising broad scales, acicular hairs and capitate hairs, but lacking glands, and indusia bearing capitate hairs.

 Distribution

North Island: Northland, Auckland, Volcanic Plateau

Altitudinal range:  0–300 m.

Thelypteris confluens occurs in lowland areas of the northern North Island from near North Cape to the Bay of Plenty and Rotorua district, with an outlying population at Lake Rotokawa near Taupō. It mostly grows close to sea level but extends to 300 m at Lake Rotoehu, near Rotorua.

Also tropical and subtropical regions from Argentina (Zuloaga et al. 2008) to Africa, Madagascar, India, south-east Asia, Malesia and Australia (Queensland, Victoria).

 Habitat

Confined to lake, swamp and marsh vegetation, or on peat in raised bogs; mostly found within dune slacks and their associated wetlands, sometimes found under mānuka, willows or pines, or rarely on old Carex mounds in open sunny sites; often associated with Typha orientalis, Machaerina juncea, Eleocharis acuta, Isachne globosa, Isolepis prolifera, Apodasmia similis, Cyclosorus interruptus and Blechnum minus. It is largely confined to coastal areas, but extends inland in wetlands on geothermally heated soils in the southern part of its range.

 Biostatus
Indigenous (Non-endemic)

The species was given a conservation status of 'At Risk / Naturally Uncommon' by de Lange et al. (2013).

 Cytology
 Bibliography
Armstrong, J.B. 1881: A natural arrangement of the New Zealand ferns founded on the system of Smith's "Historia Filicum", with critical notes on certain species. Transactions and Proceedings of the New Zealand Institute 13: 359–368.
Cheeseman, T.F. 1925: Manual of the New Zealand Flora. Edition 2. Government Printer, Wellington.
Ching, R.C. 1936: A revision of the Chinese and Sikkim-Himalayan Dryopteris with reference to some species from neighbouring regions. Bulletin of the Fan Memorial Institute of Biology 6: 237–352.
de Lange, P.J.; Murray, B.G.; Datson, P.M. 2004: Contributions to a chromosome atlas of the New Zealand flora – 38. Counts for 50 families. New Zealand Journal of Botany 42: 873–904.
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. [Declining]
de Lange, P.J.; Norton, D.A.; Heenan, P.B.; Courtney, S.P.; Molloy, B.P.J.; Ogle, C.C.; Rance, B.D. 2004: Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany 42(1): 45–76.
de Lange, P.J.; Rolfe, J.R.; Barkla J.W.; Courtney, S.P.; Champion, P.D.; Perrie, L.R.; Beadel, S.N.; Ford, K.A.; Breitwieser, I.; Schönberger, I.; Hindmarsh-Walls, R.; Heenan, P.B.; Ladley, K. 2018: Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series No. 22. [Naturally Uncommon]
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington. [Naturally Uncommon]
Fée, A.L.P. 1857–1858: Mémoires sur les Familles des Fougères. 8. Descriptions d'espèces nouvelles. Baillière, Paris.
Holttum, R.E. 1977: The family Thelypteridaceae in the Pacific and Australasia. Allertonia 1: 169–234.
Hooker, J.D. 1854–1855: The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror, in the years 1839–1843, under the command of Captain Sir James Clark Ross. II. Flora Novae-Zelandiae. Part II. Flowerless plants. Lovell Reeve, London.
Hooker, W.J. 1862: Species Filicum. Vol. 4 (part 14). Pamplin, London.
Johnston, I.M. 1924: New plants of Portuguese West Africa collected by Mrs Richard C. Curtis. Contributions from the Gray Herbarium of Harvard University 73: 31–40.
Morton, C.V. 1967: Studies of fern types, I. Contributions from the United States National Herbarium 38: 29–83.
Roux, J.P. 2009: Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23: 1–296.
Schlechtendal, D.F.L. von 1825: Adumbrationes Plantarum. Fasc. 2. Dümmler, Berlin.
Thunberg, C.P. 1794–1800: Prodromus Plantarum Capensium, quas in Promontorio Bonae Spei Africes, annis 1772-1775, collegit Carol. Peter. Thunberg. Edman, Uppsala.
Zuloaga, F.O.; Morrone, O.; Belgrano, M.J. 2008: Catálago de las plantas vasculares del Cono Sur. Vol. 1. Pteridophyta, Gymnospermae y Monocotyledoneae. Missouri Botanical Garden, St Louis.