Lepidodendron aculeatum
Part of a stem with leaf cushions.
See below for explanation.

Left: Ibbenbüren, Westfalian B.
Height of the photo 14 cm.

Above: Eygelshoven (South Limburg, NL), Westfalian A/B
Height of the photo 15 cm.

Knorria of Lepidododendron.
Knorria is a trunk of which the bark has fallen off.
Ibbenbüren, Westfalian B. Height of the photo 9 cm.

Leaf cushion of Lepidodendron.
The little quadrangle in the centre is the leaf scar.
VB is the scar of the vascular bundle of the leaflet.
P (parichnos) are the remnants of air canals going into the trunk.
L is the place where the ligule was attached. The ligule
is a very small leaflet, characteristic for clubmosses.