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 chambersii) like 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.
Fertile frond, narrower than than the regular fronds.
Curved pinnae with the wide bases.
Underside of the fertile fronds showing the arrangement of the sori.
Close up of the pinnae.
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.
Regular fronds with small rounded pinnae.
Fertile fronds packed with spore producing sori.
Stem (Rachis) note the scales and the fine hairs.
Long narrow regular fronds.
Regular (green) and fertile (brown) fronds.
Strap Water-fern (Blechnum patersonii) Has 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.
Typical plant with long strap like fronds.
Dark green strap like fronds.
A fertile frond covered with spore producing sori.
In this case the frond is divided and looks a bit like Kangaroo Fern.
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 nudum – Fishbone water-fern
Blechnum nudum – Fishbone water-fern, showing fertile fronds which are different to the barren ones (which don’t carry spores)
Blechnum nudum – Fishbone water-fern
Blechnum nudum – Fishbone water-fern, Showing the finer fertile fronds at the front and regular (Barren fronds) behind.
Blechnum nudum – Fishbone Water-fern, showing the underside of the leaflets (pinnae) which are a paler green and are attached to the frond by a broad base. The shaft of the frond (rachis) is often a shiny black colour.
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.
Blechnum cartilagineum – Gristle-fern, showing the lower stem (Stipe) which is grooved and has black scales.
Blechnum cartilagineum – Gristle-fern
Blechnum cartilagineum – Gristle-fern, The paired pinnae (leaflets) towards the base are separate and point downwards.
Blechnum cartilagineum – Gristle-fern, also has leaflets attached to the rachis by their broad base.
Blechnum cartilagineum – Gristle-fern, Underside of a fertile frond showing bands of sori either side of the mid-vein.