Dicroidium zuberi
Dicroidium zuberi is a large bipinnate species of the seed fern Dicroidium with a forked rachis. The leaves are affiliated with Umkomasia feistmantellii megasporophylls and Petruchus ''barrealensis microsporophylls.
D. zuberi was a common species in the coeval vegetation of the Sydney and Lorne Basins of New South Wales. Specimens have been found near Wairaki Hut and indicate that this species may have been as common in Scytho-Anisian vegetation of coastal New Zealand. In younger rocks younger than the late Anisian, they are outnumbered by unipinnate Dicroidium leaves such as those belonging to D. odontopteroides''.
Description
Dicroidium zuberi had large, bipinnate, thick and leathery leaves. The leaves were up to 21 cm long. The rachis is proximately forked once with opposite or sub-opposite pinnae that is imparipinnate. The largest pinnae found measure 8 cm long and 3 cm wide. The pinna rachis are between 2 and 5 cm wide with a distinct median ridge. The individual pinnules were closely spaced and frequently overlapping. The pinnules were rhomboidal or broadly oval, and usually slightly contracted at the base with entire or slightly lobed margins and an obtuse apex. The terminal pinnule of each frond was oval or oblong in shape.The stomatal frequency on both sides of the frond were similar, with irregularly oriented stomata evenly distributed over the entire surface of the leaves. Each of the stomata had typically 5 but sometimes 4 or 6 subsidiary cells that were rarely papillate and rarely in close contact with one another. The thinly cutinised guard cells were slightly sunken into the surface of the frond, appearing as an apature-like slit in a rectangular stomatal pit that was thickly cutinised on the lateral sides, with no encircling cells present.