Species

Hypolepis ambigua

Etymology

Hypolepis: From the greek hypo (under) and lepis (scale), referring to the position of the sori on the ferns
ambigua: uncertain, doubtful

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Hypolepis ambigua (A. Rich.) Brownsey et Chinnock

Family

Dennstaedtiaceae

Flora Category

Vascular - Native

NVS Species Code

HYPAMB

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.

Structural Class

Ferns

Synonyms

Hypolepis tenuifolia sensu Hook.f.; Polypodium amplum Colenso; Cheilanthes ambigua A.Rich.; Hypolepis petrieana Carse; Hypolepis punctata sensu Dobbie

Distribution

Endemic. New Zealand: Three Kings, North, South, Stewart and Chatham Islands.

Habitat

Coastal to montane. A 'weedy' species of disturbed sites in open forest, forest cleanngs, forest margins, in scrub, and in open grassland. It is often a component of brackenfield and as with H. dicksonioides, H. ambigua frequently colonises urban areas, where at times it can become a troublesome 'weed'.

Features

Rhizome long-creeping, 2–4 mm diameter, covered in red-brown hairs up to 2.5 mm long, stipes arising at intervals of 90–200 mm (abundant near growing tip, sparse elsewhere). Stipes 80–600 mm long, 1.5–5 mm diameter, red-brown at very base, pale red-brown or yellow-brown above, covered at base in red-brown hairs, up to 3 mm long, sparse above and paler. Laminae ovate or broadly ovate, 0.2-1.2 × 0.15-1.0 m, bipinnate at apex, tripinnate or quadripinnate below. Rachis red-brown or yellow-brown at base, green at apex, sparsely covered in pale brown hairs like those of stipe. Primary pinnae in 22–30 pairs, opposite or subopposite, the lowest arising at 20–50° to stem upper ones at 70–90°, the longest near the base 150–550 × 85–270 mm; lowest ones 50–240 mm apart, middle ones 15–80 mm apart; upper ones narrowly ovate or ± parallel-sided, lower ones ovate or broadly ovate narrowly winged. Secondary pinnae narrowly ovate or broadly ovate; parallel-sided, broadly winged, 50–160 × 20–53 mm those on the lower pinnae decreasing markedly in length along the pinnae. Tertiary pinnae narrowly ovate or parallel-sided, 10–30 × 5–12 mm. Quaternary pinnae (when present) 2.5–8.0 × 1.5–4.0 mm. Veins reaching margin at tooth apex. Hairs: glistening colourless non-glandular hairs on underside of lamina, costae and midribs, absent from lamina margin; brown-tinged hairs on upper surfaces abundant on midribs; 0.3–1.0 mm long (mostly c.0.5 mm), those on pinna midribs and costae often longer. Sori: one on acroscopic edge of each ultimate segment, originating away from margin; protected at maturity by slightly reflexed pinnules margin which also often bears a few short hairs at this point; hairs also often present in sorus (0.3-0.5 mm long). Spores pale, brown, echinate.

Similar Taxa

Hypolepis ambigua is most often confused with H. dicksonioides. A much less common species of mostly northern New Zealand and associated offshore islands, as well as the Kermadec Islands. Hypolepis ambiqua is readily distinguished from H. dicksonioides by the young emergent fronds which are not profusely covered in sticky, glandular hairs (indeed the fronds are also devoid of glandular hairs), and by the sorus which is only partially protected (if at all) by a marginal flap (cf. the sorus protected by a prominent marginal flap in H. dicksonioides). However, hybrids are common wherever the ranges of these two species overlap, and these can only be reliably determined by their aborted spores.

Flowering

Not Applicable - Spore Producing

Flower Colours

No Flowers

Fruiting

Not Applicable - Spore Producing

Propagation Technique

Easily cultivated from fresh spores and by the division of established plants. Hypolepis ambigua is a short-lived, and at times aggressive species such that it is probably not well suited to garden conditions.

Threats

Not Threatened

Chromosome No.

2n = 208

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Attribution

Fact sheet prepared for NZPCN by P.J. de Lange (8 November 2012).Description from Brownsey & Chinnock (1984).

References and further reading

Brownsey, P.J.; Chinnock, R.J. 1984: A Taxonomic revision of the New Zealand species of Hypolepis. New Zealand Journal of Botany 22: 43-80.

This page last updated on 6 Dec 2014