74
2 Systematic Descriptions
Fig. 2.52 a Proximal face;
small corpus in relation to
sacci, typical feature.
b Distal face
by Leschik (1956) for monolete and dilete disaccates, respectively, are regarded
here as congeneric with Illinites.
Schaarschmidt (1963) compared Limitisporites and Illinites with spores of Ulmania frumentaria (Potonie and Schweitzer 1960), emphasising the variations of the
proximal scar, from monolete to dilete and trilete. However, Schaarschmidt combined Limitisporites and Jugasporites under one genus, maintaining Illinites as
a separate genus. Schaarschmidt’s reason for maintaining two genera for similar
pollen grains were purely stratigraphical, namely that one was described from the
Upper Carboniferous of North America, while the other two were described from
the Permian of Europe. The present study maintains one genus.
Illinites tectus (Leschik 1956) (Fig. 2.53).
Occurrence: Artinskian of Collie and Wilga Basins.
Description: Disaccate. Haploxylonoid to slightly diploxylonoid. Sacci vary in
size, smaller than corpus or same size, occasionally slightly larger. Corpus very
distinct in its regular shape, size and exine thickness. Monolete, scar not always