Hymenophyllum flabellatum - Shiny Filmy-fern

Filmy Ferns

Filmy Ferns are a feature of the wet gullies and rainforests in Tarra Bulga, they are usually found as epiphytes growing on the trunks of trees and other ferns, especially Soft tree-fern (Dicksonia antarctica) as well as rocks and steep embankments . There are five different species known to occur in the park and although they are small and delicate, with a bit of practice it is easy enough to learn to tell the difference between each species. Four of them belong to the same genus (Hymenophyllum). Along with the Filmy ferns there are many species of Mosses and Liverworts that flourish in similar moist sheltered locations.

Click on the Galleries for Closer Views and Photo Descriptions

Austral Filmy-fern  Hymenophyllum australe

This fern is dark green and not particularly shiny. It is common and easy to identify by the wing which is several millimetres wide and extends all the way along the central wiry stem from the tip of the frond to the base (stipe) where it is attached. It has lots of spore producing sori at the tips of the fronds. The sori have 2 lips and they often present in pairs.

Shiny Filmy-fern   Hymenophyllum flabellatum

This is another very common fern found in the rainforest gullies. As indicated by its common name it is very shiny and it is a lighter green than the Austral Filmy-fern. The stem (stipe) does not have a wing and has a tuft of hairs at the base. The pinnae (ends of the fronds) often form a fan shape. The sori (spore producing bits) at the tips of the frond segments are wider than the rest of the leaf.

Common Filmy-fernHymenophyllum cupressiforme

Common Filmy-fern is easily found and identified by serrated margins of its outer fronds. It has large spore producing sori which are located close to the main stem (rachis) of the frond. Alpine Filmy-fern (Hymenophyllum pelatum) also has serrated margins of it frond segments (pinnae) but it has never been found in the Tarra Bulga.

Narrow Filmy-fernHymenophyllum rarum

As its Latin name suggests this fern is the hardest to find of all the local species. It will often grow among Common – Filmy fern  (e.g. Along the East-West track in the Tarra Valley picnic area) and superficially looks similar. As its common name suggests it is narrow, It has a narrow wing along its main stem which may cause confusion with Austral Filmy-fern, but a clear distinguishing feature is the the V shape made by the veins at the base of the indusium (tissue protecting the spores) at the tips of fertile frond segments. Click on the Gallery below for a better view.

Veined Bristle-fern – Polyphlebium venosum

Is the only species of the 5 ferns not in the genus Hymenophyllum. It is very common in the same habitats as the other occur. It is distinguished by its very delicate pale green shiny fronds (only one cell thick). Tiny branched veins are clearly visible on the narrow fronds. The fertile fronds have a trumpet shaped spore cover (indusium).

Hypolepis – Ground Ferns

One of the trickiest groups of Ferns to identify locally are a group of Ground ferns in the Genus Hypolepis. There are three different species recorded in the park but I have only ever found two of them which are Hypolepis glandulifera (Downy Ground-fern) and Hypolepis rugulosa (Ruddy Ground-fern). Without looking carefully these ferns can be mistaken for Bracken because they have a similar growth habit with fronds popping up from a spreading underground rhizome.

Hypolepis rugulosa (Ruddy Ground-fern) seems to be more common locally at higher altitudes in the Park (e.g. Wet Forest areas around Balook). It seems to like disturbed areas at the sides of roads and tracks. Its main feature for identification in the field is the reddy-brown colour of the frond stems (Stipes).

Hypolepis glandulifera (Downy Ground-fern)  I have found mostly at lower altitudes, especially along waterways (e.g. Tarra River and Macks Creek). Its frond stems (Stipes) are usually a pale green colour. It usually has lots of fine hairs along the stems and the new fronds are often sticky to the touch as a result of the small glands on the tips of many of the hairs. If you have a hand lens or use a digital camera with a macro setting you can see that there is a little triangular tooth close to the sori on the underside of fertile fronds. This fern was formerly known as Hypolepis punctata.

Hypolepis muelleri (Harsh Ground-fern) is also listed in Park’s flora records for the but I have yet to find any. It can be identified by the presence of tiny hairs growing in the Sori on the underside of the fertile fronds.

Dicksonia antarctica Soft tree-fern

Tree Ferns at Tarra Bulga

There are four main species of tree ferns found in Tarra Bulga National Park, (along with many other fern species) The two most common you will see are Cyathea australis (Rough tree-fern) and Dicksonia antarctica (Soft tree-fern). The Soft Tree-fern is more common in the moister areas including the rainforest gullies while the Rough tree-fern is more dominant on the slopes. Once you get you eye in it is fairly simple to tell the difference between these two, the most obvious being by comparing the trunks. The Rough tree-fern has much of its trunk covered by the remains of broken off stems (Stipes) Which are rough to the touch, while the Smooth tree-fern is soft to the touch and is covered by masses of soft hairs which are actually roots.  On this soft trunk other species of plants will often grow including tree and shrub seedlings, epiphytes and other ferns.

Cyathea australis - Rough tree-fern
Cyathea australis – Rough tree-fern, the broken of scaly frond bases (Stipes) on the upper part of the trunk of these ferns are a quick aid to their identification.
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