Asplenium’s (The Spleenworts)

Asplenium’s or Spleenworts are a very interesting group of ferns and at Tarra Bulga there are three species that can be found. One of them is common in Rainforest gullies while the other two are harder to find. It is not hard to tell each one apart although there may me some hybridisation happening between two of the species which can be confusing.

 

Mother Spleenwort  – Asplenium bulbiferum subsp. gracillimum 

This is common in the park mainly in rain forest gullies, it grows as epiphytes on tree and fern trunks as well as on shady banks, and among rocks.  It can be potentially confused with other ferns that grow in this habitat such Shiny or Leathery Shield-fern.  An impressive feature of this fern is its ability to reproduce via bulbils that can form on the tips of the fronds, giving rise to its common name “mother” as well as the Latin one. A good way to distinguish it from other ferns is to locate the linear to oblong shaped sori on the margins of the underside of the fertile fronds and to look for the many tiny brown scales on the surface of the stem and the fronds.

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Weeping Spleenwort – Asplenium flaccidum subsp. flaccidum 

Weeping Spleenwort is very uncommon in the Park, hopefully there is more hidden away in some gully that we don’t know about, but we only really know about one living plant that currently exists here. Compared to Mother Spleenwort it has linear to oblong pinnules that are not lobed.  The pinnules are widely spaced on the long Weeping Fronds. It only has a few scattered scales.

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Necklace Fern – Asplenium flabellifolium

Necklace fern is unlikely to be found in the Cool Temperate Rainforest areas in Tarra Bulga, it is more often in sheltered shady spots (e.g.) along road cuttings in more exposed sections of the park. It is more common at lower altitudes in the district, e.g. in the Warm Temperate Rainforest of Macks Creek. It is easily distinguished from the other local Asplenium species with its small slender green fronds having fan shaped leaflets (pinnae), forming what could be described as a necklace.

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Possible Hybrid???

According to some sources Aspleniums are known to hybridise across species. Several plants that I photographed along the Fern Gully Track at Bulga Park, seem to have features somewhere intermediate between Mother Spleenwort (Asplenium bulbiferum) and Weeping Spleenwort (Asplenium flaccidium).

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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.

Lance, Strap and Ray the Water Ferns

With names like Lance, Strap and Ray this lot of Water-ferns sound like rather a threatening bunch, but in reality they are probably not so tough. All preferring to grow locally in the moist shade found in Cool Temperate Rainforest. All of these species can be found fairly easily in both the Bulga Park and Tarra Valley rainforest walks. Overall seven species of Blechnum grow in Tarra Bulga National Park.

Lance Water-fern (Blechnum chambersiilike all the local water ferns (Blechnum species) apart from one have two distinctly different frond types. The ones that carry the reproductive spores on their undersides have very narrow and droopy pinnae (leaves). The regular fronds are dark green and the leaflets (pinnae) are curved and broad at the base where they are attached to the stem.

Ray Water-fern (Blechnum fluviatile) The regular fronds have small green oblong to oval shaped pinnae (leaflets) with rounded tips. The stems of the fronds (Rachis) are covered in scales as well as small hairs.

Strap Water-fern (Blechnum patersoniiHas regular fronds that are either one long strap or may have a few pairs of divided pinnae which can give them a similar look to Microsorum pustulatum (Kangaroo Fern). The edges of the fronds are usually wavy (undulating). The regular fronds are also broader closer to the tip (and skinnier at the base), they are quite tough and leathery and are a very dark green colour. The spore carrying fertile fronds are much narrower and can also be a single strap or have a few narrow sub-divisions.

Blechnums: Hard and Soft Water Fern’s

Another post in our series for people wanting to know more about the fern species in Tarra Bulga National Park and how to identify them. Here we look at two more species of Blechnum. Hard Water-fern (Blechnum wattsii) and Soft Water-fern (Blechnum minus).

Blechnum wattsii – (Hard Water-fern) is much more common than the Soft Water-fern at Tarra Bulga and is found in both Cool Temperate Rainforest and Wet Schlerophyll forest areas. It has tough dark green fronds, a key feature is that the lower leaves (pinnae) on each stem (rachis) are only slightly smaller than the others.

Blechnum minus – (Soft Water-fern) is locally more restricted in its distribution and mainly confined to the banks of water-bodies. It’s fronds are a lighter shade of green and the margins of the pinnae are more undulating or wavy. A key feature of their identification is that the lower leaves (pinnae) on each stem is are much shorter than the rest and they are also widely spaced apart.

Both species are dimorphic meaning that the fertile fronds that contain the spores are different to the regular fronds, for both of these species they are a lot more slender than the regular fronds.

Related Posts

Blechnum Species in Tarra Bulga

There are seven different species of the fern genus Blechnum (Water Ferns)  in Tarra Bulga National Park and with a bit of background knowledge it is relatively easy to tell them apart. This post will focus on the identification of Blechnum nudum (Fishbone Water-fern) and Blechnum cartiliagineum (Gristle Fern), which unlike the other 5 species both have leaflets (pinna) being directly attached to the regular fronds by a broad base. The easiest way to tell them apart is by their fertile fronds.

Blechnum nudum (Fishbone Water-fern) is usually found in clumps in wet forest and gullies, it is reasonably common around Tarra Bulga.

Blechnum cartiliagineum (Gristle Fern) is less common in Tarra Bulga and is more commonly found in gullies or sheltered spots at lower elevations downstream from the park.

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.