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.

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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.

Senecios (Fireweeds) at Tarra Bulga

Despite having weed as part of their common name and belonging to the same genus as the much maligned Ragwort (Senecio jacobaea), there are several species of Senecio in Tarra Bulga National Park that are locally indigenous and very much desirable. They are most commonly found in open and disturbed areas, usually where there is a break in the canopy or on the side of  roads and tracks. Their ability to quickly colonise an area like this means they can compete against real weeds that may potentially invade these sites.

Senecio linearfolius (Fireweed Groundsel) grows to about 1.5 metres high and usually has smooth narrow lance shaped leaves with regularly spaced teeth. When in flower it can be identified by the 5 yellow ray florets (like petals) on each flower head. The flowers heads are clearly different from the other species that exist in the park (described below).

Senecio pinnatifolius (Variable Groundsel) is an amazingly variable species with huge differences in the size and form of the plant possible. What is consistent however is the attractive flower heads which are wider than the other species (up to 15 mm across) and have up to 14 yellow (petal like) ray florets, The unopened flower buds are bell shaped. The foliage is so variable that it is not useful for identification apart from the fact that the leaves are sessile (which means they are connected to the stems without a stalk) and it is usually hairless.

Senecio minimus (Shrubby Fireweed) has more consistent leaf characteristics so you can usually easily identify it without seeing its flowers. The leaves are lance shaped and have evenly spaces small raspy teeth on the margins. Where the leaf base is attached to the stem there are two lobes (auricles). The stems themselves have vertical ridges and are usually quite purple. The flowers heads are clearly different from the other two species. There are large clusters of them at the end of flower stalks but they do not have any petal like ray florets.

Senecio jacobaea (Ragwort) is a noxious weed, sometimes found in disturbed sites in Tarra Bulga, but it is far more common in in cleared farming areas nearby. It has similar looking but smaller flowers when compared with Senecio pinnatifolius, but it has distinctive deeply lobed leaves which make it clearly identifiable.

Olearias

Tarra Bulga National Park has three different species of Olearia which are members of the daisy family. Two of them can be a little tricky to tell apart, however one is clearly different to the others. From casual observation all of them have similar looking flowers and the best way to tell them apart is by examining the leaves.

Olearia lirata – (Snowy daisy-bush) is a very common species in the park, although it is not usually present in the rainforest gullies; it is a dominant shrub in the wet sclerophyll forest areas (which is the most common vegetation type in the park). It is a small to medium sized shrub and its medium sized leaves are lance shaped and usually green and shiny above and grey and hairy underneath.

Olearia phlogopappa – (Dusty daisy-bush) is less common in the park than Olearia lirata and is  and mostly found in the more disturbed areas; it is also a small to medium sized shrub. It has narrower leaves, that are more greyish and not shiny (hence dusty) with tiny hairs on the underside. The leaves also usually have blunt teeth along their margins.

Olearia argophylla – (Musk daisy-bush)is the third species. It is a large shrub almost to the size of a small tree. Its leaves are much broader and larger than the other two species, they are green on the top and whitish or silvery underneath. It can occur in all forest types within Tarra Bulga, including the rainforest gullies.

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Local Cassinias

This is the time of year when most of the daisy species in Tarra Bulga are in flower. A number of species look quite similar and a bit of knowledge is often needed to tell one from another.They are all medium shrubs with narrow linear leaves and similar looking cauliflower like flower-heads.

One group are the Cassinias’ there are three separate species and all of them occur in the more open and exposed sections of the park rather in the shaded and protected gullies

Cassinia aculeata – (Common Cassina or Dogwood) has the the shortest and narrowest leaves of the three. If you look underneath the leaves you can see that they are curled over at the edges. Another distinguishing feature is that the new flowers are sometimes pink rather that white.

Cassinia longifolia – (Shiny Cassinia) has broader and longer leaves and the new leaves are noticeably shiny and sticky to touch. The underside of the leaves are covered in short dense hairs and the vein down the middle is very prominent.

Cassinia trinerva – (Three-veined Cassinia)Has leaves that are also broader and longer than Common Cassina, they are quite soft and not shiny or sticky. They have a big vein running down the middle of the leaf and two smaller veins that run a millimetre or two inside the leaf margins.

Ozothamnus ferrugineus (Tree Everlasting) is a fourth species that can be confused with the Cassinia’s as it is a similar size and has similar leaves. It’s leaves are around the same size as Cassinia longifolia (Shiny Cassinia) but its leaf margins are usually a little wavy. With close examination the flowers are clearly different to Cassinias, they have little bracts around the individual florets.

Clematis Season

There are two species of Clematis that occur in Tarra Bulga National Park and surrounding forest areas, Forest Clematis (Clematis glycinoides) and Mountain Clematis (Clematis aristata) and it can be very difficult to tell the difference between them. They are climbing plants that can climb high into trees and produce a mass of attractive white flowers in Spring. Both of them have leaves in groups of three of a similar size, Clematis aristata commonly has teeth or serrations on the leaf margins but both species show variation.

Clematis leaf comparison

There are two main ways to tell the difference between the two out in the field. The first is flowering time. Clematis glycinoides tends to flower in early spring, with most of its flowering finished by mid-October, then Clematis aristata seems to take over to be the dominant flowering species for a month or so, although locally it is less common. The other way is a key but subtle difference in the flowers. If you look carefully at a flower the tips of the anthers have little appendages, In Clematis glycinoides they are very short <1mm or even absent. In Clematis aristata they are clearly longer usually around 2 or 3mm long.

Clematis Flowers
Clematis glycinoides (Forest Clematis) and Clematis aristata (Mountain Clematis) flowers compared.

Climbers and Ground Covers of Tarra Bulga

Images provided courtesy of Park Ranger – Craig Campbell.