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tasmanian liverworts - pallaviciniaceae
symphyogyna
 1. S. hymenophyllum |
 2. Sporophytes |
 3. close-up of thallus |
We discovered this growing adjacent to Aneuria rodwayi on a near vertical south facing road bank which stays damp all through winter if not during most of the year.
It was obviously a member of the Pallaviciniaceae family which includes Podomitrium, Symphyogyna and Pallavicinia genera. We ruled out Podomitrium because the thalli had teeth on the margains. Beyond that we had to wait for sporophytes to develop for more precise identification.
We lost sight of this plant for some time then re-discovered it three months later with sporophytes developing. Utas key states that Symphyogyna has 'base of sporophyte encased in a thick fleshy tube. Male sex organs with scales obscuring midrib'.
This contrasts with Pallavicinia where the 'base of sporophyte is surrounded by a tubular structure. Male sex organs (has) scales flanking both sides of the midrib'
As the images show, the description of Symphyogyna fits our specimen - the third image shows the scales over the midrib.
There are a reported 4 species of Symphyogyna in Tasmania, the most common being S. hymenophyllum. S. interrupta has unbranched thallus and is fairly uncommon. The remining two species, S. lehmanniana and S. rhodina appear to be obscure entities whose existence seems to be in doubt.
pallavicinia
We discovered this fragment tangled with a moss (Pyrrhobryum mnioides) we had kept moist for several weeks. Apparently it had made new growth which was considerably narrower than the older fragment which was around 2.5 mm wide. Until such time as we discover another population we are unable to determine if our small sample is typical of the species.
 4. thallus |
 5. tooth |
 6. branching |
 7. cells |
Description: The thallus had a thickened mid-vein but the 'wings' (pix 4) comprise of single cells. It is symmetrical and flat on both dorsal and ventral sides as far as could be determined. The teeth (pix 5) are tiny, comprising of 1x2 cells, pointing forward and curving in. There were small numbers of white rhizoids at the base of branches. Cells are elongated along the wings (pix 7) but much more so along the mid-vein.
We tried using the Lucid Key cited below which yielded three results for thallose liverworts with ventral branching (pix 6). By elimination we arrived at Pallavicinia which is reported to have three species in Tasmania.
It is not P. rubristipa which is dendroid and has a concave thallus. Here it gets a little confusing because M&F consider records of Australian P. lyelli to be P. pseudolyelli with 'very undulating margins' and no teeth so we had to discard this as well. The third species is P. xiphoides which is reported to have teeth 'several cells long' and this does not match our sample.
We shall have to leave it as a Pallavicinia species for the present.
Literature:
- Meagher, D., & Fuhrer,
B., A
Field Guide to the Mosses and Allied Plants of Southern
Australia, (ISBN 0 642 56828 6), Flora of Australia
Supplementary Series, Number 20 - Australian Biological Resources
Study/The Field Naturalists Club of Victoria, 2003 (M&F)
- Key
to Australasian Liverwort and Hornwort Genera (ISBN 0 642
56840 5) by Australian Biological Resources Study on CDRom is a
comprehensive interactive key to 181 genera of liverworts and
hornworts. (Lucid Key)
Page URL: http://www.bluetier.org/Liverwort/pallaviciniaceae.htm