Arachniodes aristata.
The Prickly Shield Fern is in Family Dryopteridaceae.
There are about 50 species with one native to Australia and occuring in Queensland.
They are medium sized, clumping ferns with shiny dark green fronds up to 120 cm long.
The long creeping rhizome is densely covered with triangular or linear reddish-brown, slightly
toothed scales up to 9 cm long.
The scaly frond stalk can be up to 60 cm long.
The upper surface of the stalk (and the midrib of the frond and its side branches) has a deep narrow groove.
The groove on the midrib opens to receive the grooves on the side branches (in some similar genera
it does not open – the ridge beside the groove is continuous).
There are some scales on the midrib.
The frond blade is divided 3 times although the lower segments can divide again.
The tip tapers to a sharp point.
The leaflets and their segments are on short stalks except for the terminal segments.
The ultimate leaflet segments are up to 20 mm long and ovate.
Their lower side is obliquely cut away and the base is unequal.
The edges have teeth and the tip is a sharp point.
The end segments on the secondary stalks are undivided.
The basal leaflets have an enlarged segment on the lower side of the base.
The sporangia are in rounded sori on the underside of fertile fronds.
There are up to 8 pairs, each midway between the midrib and the edge of the segment.
They have a brown indusium with a dark centre.
Spores are dark brown.
J.F.
