Asplenium flaccidum subsp. haurakiense Brownsey

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.

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.

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.

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

n = 72 (Brownsey 1977b).

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.