Tag Archives: Asplenium hookerianum

NZ fern colonises Australia, twice

4 February 2011 – 10.38am
Asplenium hookerianum

Hooker's spleenwort fern. Near Levin, New Zealand. (c) Leon Perrie.

It is not just people crossing the ditch – a little New Zealand fern has also emigrated to Australia, and not just once but twice.

This is the first known case amongst ferns or seed plants of the same species dispersing twice across the Tasman Sea.

Hooker’s spleenwort fern, or Asplenium hookerianum, is a close relative of the hen & chickens ferns. Hooker’s spleenwort is widespread and common in New Zealand, but rare in Australia, with only a few, small populations in each of Victoria and Tasmania.

DNA analyses of the populations of Hooker’s spleenwort were carried out by researchers from Te Papa, Massey University, and the University of Melbourne.

26 genetic variants were found in New Zealand, but only one each in Victoria and Tasmania. Not only are the Australian variants at the tips of the genetic family tree, they are more closely related to variants in New Zealand than to each other.

This research was recently published in the journal Australian Systematic Botany.  Email me if you would like a copy of the paper: leonp@tepapa.govt.nz

Many plant species are known to have dispersed across the Tasman Sea, in either direction. Numerous New Zealand species also occur in Australia (about 50% in ferns), and more have close relatives there. But, it remains an open question how common multiple dispersals within a species are.

By Leon Perrie | Posted in Ferns, Plants | Also tagged , , , , , , , | Comments (3)

Identifying Asplenium hookerianum in Victoria

10 March 2010 – 2.28pm

From our search in Victoria’s Alpine National Park, we suspect the rare Asplenium hookerianum (Hooker’s spleenwort) is actually much more common there than previously recognised. But more searching is needed to confirm this. 

Searching for Asplenium hookerianum in Victoria’s Alpine National Park. 

Asplenium hookerianum can be distinguished from the other ferns it occurs with in Victoria by its being fertile at a small size (c. 5 cm), with linear reproductive structures, and fronds that are twice divided with rounded frond segments. 

Small plants of Asplenium flabellifolium (necklace spleenwort) can resemble Asplenium hookerianum. However, the latter has bi-pinnate (twice divided) fronds, discernible at the base of even small fronds. 

A small frond of Asplenium hookerianum (Hooker’s spleenwort), Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

Asplenium flabellifolium (necklace spleenwort), Armidale, NSW, Australia. Photo by Leon Perrie, Curator. © Museum of New Zealand.

Asplenium hookerianum (left top and middle) and Asplenium flabellifolium, Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

 Polystichum proliferum (mother shield fern) and Cystopteris tasmanica (bladder fern) have frond segments with pointed apices and round rather than linear reproductive structures. Further, Polystichum proliferum usually does not become fertile until a size bigger than Asplenium hookerianum. 

Polystichum proliferum (mother shield fern), Toolangi, Victoria. Photo by Leon Perrie. © Leon Perrie, Wellington.

 Asplenium gracillimum (a hen & chickens fern) also usually does not become fertile until a size bigger than Asplenium hookerianum. The latter also differs in its frond segments being more stalked. 

Asplenium gracillimum (a hen & chickens fern), Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

By Leon Perrie | Posted in Ferns, Plants | Also tagged , , , | Comments (1)

Searching for a rare Australian fern

9 March 2010 – 5.08pm

While visiting family in Melbourne, I took the opportunity to go fern hunting.

Asplenium hookerianum (Hooker’s spleenwort), Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

Asplenium hookerianum is a rare fern in Australia.  With Melbourne University’s Daniel Ohlsen and Mike Bayly, we went searching for the two populations recorded from Victoria’s Alpine National Park. 

How to recognise Asplenium hookerianum in Victoria.

We were successful, relocating the known populations and finding a new one.  We recorded a total of 450-500 individuals, some 200 more than previously noted.

In Victoria, Asplenium hookerianum appears restricted to rock overhangs in deep gorges.  It was odd seeing it in Eucalyptus forest.  In New Zealand, Asplenium hookerianum is much less fussy, being common on the forest floor. 

Lara, pointing to Asplenium hookerianum on this rock wall, and Daniel. Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

Asplenium hookerianum habitat (at the bottom of this gorge), Alpine National Park, Victoria. Photo by Leon Perrie, Curator. © Museum of New Zealand.

We wonder whether the Australian populations are derived from New Zealand, or vice versa.  We hope to test this using DNA analyses.

Findings from our previous investigations of New Zealand Asplenium hookerianum:

By Leon Perrie | Posted in Ferns, Field trips, Plants | Also tagged , , , | Comments (5)
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