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Calamites Xylem
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| A close-up of the central pith of Calamites reveals tubular structures called carinal canals, which are surrounded by primary xylem. Secondary xylem can be seen radiating away from the carinal canals. In this specimen, medullary rays can be seen between the carinal canals and secondary xylem. With this close-up we can make sense of the exterior ribs found on Calamites pith casts. The ribs correspond to the rays. The depressed areas between the ribs are where the carinal canals extended into the pith cavity. |
 Calamites Pith Cast Carboniferous West Virginia 16 cm long x 6.5 cm diameter |