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.