Classification
Class
Polypodiopsida
Subclass
Polypodiidae
Order
Osmundales Link
Family
Osmundaceae Martinov
Genus
Leptopteris C.Presl
 Nomenclature
Scientific Name:
Leptopteris hymenophylloides (A.Rich.) C.Presl, Suppl. Tent. Pterid. 71 (1845)
Synonymy:
  • ≡ Todea hymenophylloides A.Rich., Essai Fl. Nouv.-Zél., 97, t. 16 (1832)
  • ≡ Osmunda hymenophylloides (A.Rich.) J.B.Armstr., Trans. & Proc. New Zealand Inst. 13: 368 (1881)
Lectotype (selected by Brownsey 1981): Baie des Îles [Bay of Islands, Northland], Nouvelle Zélande, Décembre, Astrolabe, Herb. A. Richard in Herb. Drake, P 00523203!
  • = Todea pellucida Carmich. ex Grev. & Hook., Bot. Misc. 3: 232 (1833)
Lectotype (selected by Brownsey 1981): banks of the Cowa-cowa R. [Kawakawa R.], Bay of Islands, New Zealand, A. Cunningham, Oct. 1826, K! (photo WELT E466/3)
  • = Todea marginata Colenso, Trans. & Proc. New Zealand Inst. 29: 419 (1897)
  • ≡ Leptopteris marginata (Colenso) C.Chr., Index Filic. 390 (1906)
Lectotype (selected by Brownsey 1981): no locality, Herb. W. Colenso, WELT P003363!
Etymology:
From the Latin Hymenophyllum (a filmy fern), and -oides (like), a reference to the texture of the frond.
Vernacular Name(s):
heruheru; single crepe fern
 Description

Rhizomes erect, short or sometimes forming woody trunks up to 500 mm (rarely to 1000 mm) tall. Fronds 220–980 mm long. Stipes 110–480 mm long, pale brown, sparsely woolly hairy. Laminae 2-pinnate-pinnatifid, elliptic, ovate, or triangular, 140–725 mm long, 95–330 mm wide, green, membranous and translucent, sparsely hairy particularly on abaxial surfaces of costae of primary and secondary pinnae. Primary pinnae in 15–30 pairs, narrowly ovate to narrowly triangular, with acute apices, widely spaced along rachis; the longest at or below the middle of the rachis, 60–180 mm long, 25–55 mm wide; the basal pair 50–120 mm long. Secondary pinnae oblong or narrowly elliptic, 14–28 mm long, 5–10 mm wide, sessile or adnate, divided most of the way to the midrib. Ultimate lamina segments linear, attenuate, flattened in plane of frond. Sporangia scattered on abaxial surfaces, confined to proximal part of primary and secondary pinnae.

 Recognition

Leptopteris hymenophylloides has very thin, membranous fronds, resembling filmy ferns and can be confused with them when very young. It is distinguished from L. superba by its longer stipe, triangular lamina, longer and broader pinnae, and by its ultimate laminal segments, which are flattened in the plane of the frond. The basal pinnae (50–120 mm long) are significantly longer than those in L. superba (1–20 mm long) and this character alone will usually distinguish the two species.

 Distribution

North Island: Northland, Auckland, Volcanic Plateau, Gisborne, Taranaki, Southern North Island.

South Island: Western Nelson, Sounds-Nelson, Marlborough, Westland, Canterbury, Otago, Southland, Fiordland.

Chatham Islands, Stewart Island.

Altitudinal range: 10–950 m.

The species has a predominantly northern distribution. It is abundant in much of the North Island, especially in lowland and montane areas, from 10 to 950 m, but is uncommon in truly coastal regions, especially on the east coast and in Taranaki. In the South Island it is more common in lowland regions, but extends locally to 925 m in montane areas of inland Marlborough; it is absent from much of the high country.

Leptopteris hymenophylloides distribution map based on databased records at AK, CHR and WELT. Image: K. Boardman © Landcare Research 2014
Leptopteris hymenophylloides distribution map based on databased records at AK, CHR and WELT. Image: K. Boardman © Landcare Research 2014
 Habitat

A terrestrial fern that occurs in lowland to montane areas, under kauri, podocarp, broadleaved and beech forest, especially on damp banks and along streams, but also on drier valley sides and ridge tops. It frequently occurs with L. superba, but the latter is usually confined to damper sites and valley floors.

 Biostatus
Indigenous (Endemic)
 Hybridisation

Leptopteris hymenophylloides and L. superba frequently occur together in wet, forested areas, and they hybridise readily. Hybrids (Leptopteris ×intermedia) show regular bivalent formation at meiosis and have spores of normal appearance, but there is no evidence for second-generation hybrids (Brownsey 1981).

 Cytology

n = 22 (Manton 1950; Brownlie 1958; Brownsey 1981).

 Images
Leptopteris hymenophylloides: primary pinna showing deeply divided secondary pinnae, hairs on the underside of the pinna midribs, ultimate laminal segments lying in the plane of the frond, and scattered sporangia. Image: L.R. Perrie © Te Papa 2012 CC BY-NC 3.0 NZ
Leptopteris hymenophylloides: primary pinna showing deeply divided secondary pinnae, hairs on the underside of the pinna midribs, ultimate laminal segments lying in the plane of the frond, and scattered sporangia. Image: L.R. Perrie © Te Papa 2012 CC BY-NC 3.0 NZ
 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.
Brownlie, G. 1958: Chromosome numbers in New Zealand ferns. Transactions of the Royal Society of New Zealand 85: 213–216.
Brownsey, P.J. 1981: A biosystematic study of a wild population of Leptopteris hybrids in New Zealand. New Zealand Journal of Botany 19(4): 343–352.
Brownsey, P.J.; Given, D.R.; Lovis, J.D. 1985: A revised classification of New Zealand pteridophytes with a synonymic checklist of species. New Zealand Journal of Botany 23(3): 431–489.
Brownsey, P.J.; Perrie, L.R. 2014: Osmundaceae. In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 4. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand ferns and allied plants. Edition 2. David Bateman, Auckland.
Christensen, C. 1905–1906: Index Filicum. Hagerup, Copenhagen.
Colenso, W. 1897: A description of some new indigenous New Zealand forest ferns. Transactions and Proceedings of the New Zealand Institute 29: 414–421.
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. [Not Threatened]
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. [Not Threatened]
Greville, R.K.; Hooker, W.J. 1833: Enumeratio filicum. Botanical Miscellany 3: 216–232.
Large, M.F.; Braggins, J.E. 1991: Spore atlas of New Zealand ferns and fern allies. SIR Publishing, Wellington.
Manton, I. 1950: Problems of cytology and evolution in the Pteridophyta. Cambridge University Press, Cambridge.
Presl, C.B. 1845: Supplementum Tentaminis Pteridographiae. Haase, Prague.
Richard, A. 1832: Essai d'une Flore de la Nouvelle Zélande. In: Dumont d'Urville, J. Voyage de découvertes de l'Astrolabe. Botanique. Tastu, Paris.