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 wattsii – Hard Water-fern – Showing a typical dark-green frond
Blechnum wattsii – Hard Water-fern – Showing the narrow fertile fronds
A typical spreading colony of Hard Water-fern – Blechnum Wattsii
Showing lower pinnae of Hard Water-fern at the top of the photo which are only slightly smaller than the ones on the rest of the frond.
Blechnum wattsii – Hard Water-fern – showing both fertile fronds (taller and narrower) and regular fronds.
Blechnum wattsii – Hard Water-fern – showing where the pinnae are attached by a very sort stalk
Blechnum wattsii – Hard Water-fern – pinnae – Underside of pinnae, which are also attached to the stem by a very short stalk.
Blechnum wattsii – Hard Water-fern – Underside Fertile Pinnae, which are narrow and covered in spore producing sori.
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.
Blechnum minus – Soft Water-fern a typical frond
Blechnum minus – Soft Water-fern Growing in a typical situation adjacent to water.
Blechnum minus – Soft Water-fern – Pinnae are attached to the stem by very short stalks.
Blechnum minus – Soft Water-fern new frond (Crozier)
The back of a fertile Soft Water-fern frond covered in spore producing sori
Lower pinnae of the Soft Water-fern, are much shorter than the ones along the rest of the stem and are more widely spaced apart, (the grass is covering up a another pair of pinnae even lower down the stem).
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.
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.
Flower head, in this case showing the Pink Form
Showing the underside of the narrow leaves that are hair below with recurved margins.
Showing white flowerheads this time.
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.
Showing the Shiny upper-side of the leaf which can be sticky and has a prominent mid-vein.
Showing the underside of the leaf with dense hairs and the mid vein.
Typical shiny leaves
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.
Underside of leaves showing the 3 veins that give the species its name.
Cassinia trinerva – Three-nerved Cassinia
Flowerhead which again looks very similar the the other 2 species in the park.
Cassinia trinerva – Three-veined Cassinia
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.
Leaves look fairly similar to Shiny Cassinia but the edges tend to be a little undulating.
Underside of the leaves has a creamy white – felty texture.
Side view of flowers, which can be identified by the separate mini florets.
Another view of the flowers, Note the difference to Cassinias.
They also have a woody trunk, Which is probably the source of their common name.