Classification
 Nomenclature
Scientific Name:
Asplenium flaccidum subsp. haurakiense Brownsey, New Zealand J. Bot. 15: 70 (1977)
Synonymy:
  • Asplenium haurakiense (Brownsey) Ogle, New Zealand J. Bot. 25: 591 (1988)
Holotype: Oneroa Beach, Waiheke Island, Auckland, P.J. Brownsey NZ 894, 1 Sept. 1974, CHR 308926 (on two sheets)!; isotype WELT P009942!
Etymology:
haurakiense (Latin) – from the Hauraki Gulf, North Island, New Zealand.
 Description

Rhizome scales ovate or narrowly ovate, 2–5 mm long, 0.7–2 mm wide, clathrate with very thick cell walls. Fronds 45–680 mm long. Stipes 25–280 mm long, bearing scattered ovate scales with thickened cell walls. Laminae usually 2-pinnate-pinnatifid or rarely 1-pinnate-pinnatifid, elliptic or narrowly elliptic or ovate, 22–400 mm long, 18–200 mm wide, stiff and upright. Primary pinnae in 1–19 pairs below pinnatifid apex, not or only slightly overlapping; the proximal pinnae and those at mid-lamina narrowly ovate or ovate; the longest 10–180 mm long, 6–30 mm wide (excluding basal acroscopic pinnule), apices forming undivided acuminate segments 2–20 mm long. Secondary segments (excluding the basal acroscopic one) gradually decreasing in length along each primary pinna to the distal end, the longest secondary segments 5–17 mm long, 1–10 mm wide; the basal acroscopic secondary pinna usually enlarged or greatly extended, up to 55 mm long and 15 mm wide, divided into linear or oblong or rarely bifid tertiary segments. Indusia 2–7 mm long. Mean spore size 40–49 μm long, 26–33 μm wide; perispores sometimes winged, usually lacking ridges.

Note: excludes collections from the Kermadec Islands.

 Recognition

Differences between subsp. haurakiense and subsp. flaccidum are discussed under A. flaccidum subsp. flaccidum.

Asplenium flaccidum subsp. haurakiense can be difficult to separate morphologically from A. appendiculatum, although their distributions barely overlap. Asplenium flaccidum subsp. haurakiense usually has an enlarged basal acroscopic secondary segment which is markedly larger than the adjacent segment, whereas in A. appendiculatum the secondary pinnae decrease gradually in size from the proximal to distal end of each primary pinna.

 Distribution

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

Kermadec Islands, Three Kings Islands.

Altitudinal range: 0–250 m.

Asplenium flaccidum subsp. haurakiense occurs on the Kermadec Islands, the Three Kings Islands, the east coast of Northland and Auckland, the islands of the Hauraki Gulf and Coromandel Peninsula, extending locally into the Bay of Plenty. It grows from sea level up to 250 m on Hen Island.

 Habitat

Asplenium flaccidum subsp. haurakiense is a terrestrial fern that grows most frequently on coastal rocks within the immediate vicinity of salt spray, amongst flax, or in coastal scrub and coastal pōhutukawa and karaka forest, or under mānuka and kānuka. Occasionally it is found growing epiphytically on Metrosideros excelsa or M. kermadecensis. It is sometimes found growing in pied shag or petrel colonies, where it can be much larger.

 Biostatus
Indigenous (Endemic)
 Hybridisation

There is evidence that A. flaccidum subsp. haurakiense hybridises with A. oblongifolium (Brownsey 1977a), A. decurrens and A. shuttleworthianum (newly recorded here).

 Cytology

n = 72 (Brownsey 1977b).

 Notes

The name Asplenium haurakiense (Brownsey) Ogle was published in Vol. 25, No. 4 of the NZ Journal of Botany. Although dated 1987, it was not published until April 1988, as indicated in Vol. 26, No. 1.

 Bibliography
Brownsey, P.J. 1977a: Asplenium hybrids in the New Zealand flora. New Zealand Journal of Botany 15: 601–637.
Brownsey, P.J. 1977b: A taxonomic revision of the New Zealand species of Asplenium. New Zealand Journal of Botany 15(1): 39–86.
Brownsey, P.J.; Perrie, L.R. 2018: Aspleniaceae. In: Breitwieser, I.; Wilton, A.D. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 18. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand ferns and allied plants. Edition 2. David Bateman, Auckland.
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. [as Asplenium haurakiense (Brownsey) Ogle] [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. [as Asplenium haurakiense (Brownsey) Ogle] [Not Threatened]
Ogle, C.C. 1988 ("1987"): Taxonomic changes in Asplenium (Aspleniaceae; Filicales) in New Zealand. New Zealand Journal of Botany 25(4): 591–593.
Shepherd, L.D.; Perrie, L.R.; Brownsey, P.J. 2008: Low-copy nuclear DNA sequences reveal a predominance of allopolyploids in a New Zealand Asplenium fern complex. Molecular Phylogenetics and Evolution 49: 240–248.