| In these photos you can see some of the features typical of arborescent
lycopods of the Pennsylvanian coal swamp. They can be collectively called
lepidodendrids, based on the diamond-shaped "snakeskin" type pattern produced
by the helically arranged leaf cushions. On the left
is a lower magnification view of this type of pattern, showing the general
features of many of these trees. Each leaf abscissed, so that if you are
looking, as you are here, at the outside of the stem, you can see a characteristic
appearance. On the right is a higher magnification
photo showing details of leaf cushions. Each diamond shaped cushion has
a smaller central area called the leaf base where the leaf attached. In
the center of the leaf base you can see the leaf trace, or vein to the
leaf. The vertical stripe running down each cushion is probably the result
of increased girth from secondary cortical growth inside the stem. Click
for next slide. |
