... Family Hymenophyllaceae
While at Fern Glade recently I took some time to photograph a small
epiphytic fern which I often see growing on the trunks of Tree ferns.
They are known as Filmy ferns because in most species the leaf is only
one cell thick, giving them a filmy appearance. As always, there are
exceptions such as Sphaerocionium applanatum, where the leaf
appears to be thicker due to a covering of tiny hairs. One
characteristic of the Filmy Ferns is that they lack any stomata. Stomata
are small openings on the leaf that allow the exchange of gasses,
including water vapour. They close when dry to prevent dessication.
Not having this ability, the filmy Ferns can only survive in very moist areas.
Tasmania has three genera of Filmy Ferns with a total of eight
species. They are found in wet forests on rocks or as epiphytes. Using
the Key to Tasmanian Vascular Plants I was able to identify the fern in my photographs as Hymenophyllum flabellatums.
However, in the background of some of my other photos there appear to
be other species of Filmy Fern growing on the same trunk. I’ll have to
look a little closer next time around.