FloraOfNewZealand-Ferns-15-BrownseyPerrie-2016-...
Hymenophyllaceae is the largest family of ferns in New Zealand with 31 indigenous species, of which 17 are endemic. In the interests of nomenclatural stability and because of the difficulty of identifying segregate genera morphologically, two umbrella genera, Hymenophyllum and Trichomanes, are recognised here. Abrodictyum, Crepidomanes and Polyphlebium are segregates of Trichomanes sensu lato, and Cardiomanes is now included within Hymenophyllum.
The family comprises terrestrial or epiphytic ferns that have long-creeping or erect rhizomes, an indumentum of hairs, membranous and often translucent laminae, marginal sori, tubular or bivalvate indusia, extended receptacles, sporangia with an oblique annulus, and trilete, green spores. In New Zealand, most species of Hymenophyllum are characterised by their bivalvate indusia and receptacles that are included within the valves, but three New Zealand species have receptacles that are sometimes exserted for a short distance beyond the indusium, and in H. nephrophyllum the indusia are urceolate. The rhizomes are generally almost glabrous or bear only scattered hairs near the stipe bases. By contrast, species of Trichomanes have tubular indusia with long-exserted receptacles, and rhizomes which are abundantly covered in red-brown hairs. The three trichomanoid segregates in New Zealand are difficult to separate morphologically and are distinguished primarily on the basis of molecular differences.
DNA sequence data indicates that the hymenophylloid clade has diversified more recently than the trichomanoid clade. It also displays less morphological variation and ecological diversification. Ten subgenera in Hymenophyllum are recognised worldwide, of which nine occur in New Zealand and two are endemic to the region, suggesting that New Zealand and the Pacific is a centre of diversity for the genus.
Of the 31 species of Hymenophyllaceae occurring in the New Zealand region, three are found only on the Kermadec Islands or with an outlying population in Northland. Of the remaining 28 species, 21 have a widespread or westerly distribution in the North Island but are largely, or completely, confined to western parts of the South Island, reflecting a preference for wetter habitats. Three species, Hymenophyllum australe, H. cupressiforme and Trichomanes endlicherianum, are widespread in the North Island, but in the South Island are more common on the eastern side. Four species, Hymenophyllum minimum, H. multifidum, H. peltatum and H. villosum, are widespread in both islands. Eight species, H. bivalve, H. malingii, H. minimum, H. peltatum, H. pulcherrimum, H. rufescens, H. villosum and Trichomanes colensoi are rare or absent north of latitude 38° S; three species, Trichomanes elongatum, T. endlicherianum and Hymenophyllum cupressiforme, are rare or absent in the southern half of the South Island, and a further three, H. flexuosum, H. malingii and Trichomanes colensoi, extend to the southern South Island but are absent from Stewart Island.
Additional Information
| Field | Value |
|---|---|
| Data last updated | 7 March 2016 |
| Metadata last updated | 24 March 2015 |
| Created | 24 March 2015 |
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| License | CC-BY 4.0 (Attribution) |
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