There are 2 genera in Psilotaceae (the Whisk ferns).
The 2 species in Psilotum have scale-like leaves while Tmesipteris species have large leaves.
Both Psilotum species are endemic in Australia — P. complanatum has flattened shoots and P. nudum has angled ones.
Psilotum nudum, the Skeleton Fork Fern, is an epiphytic or terrestrial plant common in eastern Queensland.
It has a creeping or clumped rhizome.
The aerial shoots, up to 80 cm long, branch numerous times in all directions.
The branches have 3 to 7 longitudinal ridges with pores confined to the grooves in between.
Sterile leaves are pale yellow-green, 1 to 1.25 mm long and arise from the ridges.
The fertile stems are similar but the leaves on them are forked.
These forked leaves bear the sporangia which are fused into a 3 lobed yellow synangium up to 2 mm long by 2.5 mm wide.
Spores are white.