The Virtual Petrified Wood Museum.  Dedicated to the Exhibition and Educational Study of Permineralized Plant Material
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Calamites Stem
Calamites Labeled
Arborescent Horsetail
Calamites
Bieland, Maranhao Province, Brazil
Pedra de Fogo Formation
Permian
10.5 cm x 8 cm
The stem of this Calamites specimen was compressed during the fossilization process. The stem is made mostly of secondary xylem. Medullary rays can be seen radiating from the center to the periphery. Bark is not preserved on this Permian aged specimen from Brazil. The periphery of the inner bark of Calamites possessed air spaces called valecular canals.
Calamites Stem Cross-Section
Arborescent Horsetail
Calamites
Bieland, Maranhao Province, Brazil
Pedra de Fogo Formation
Permian
11.5 cm x 10 cm


The permineralized Calamites stem from Brazil exhibits a partially hollowed out pith. The pith would often fill with sediment during fossilization creating an internal cast or steinkern.
Calamites Pith Cast
Calamites Pith Cast
Carboniferous
West Virginia
16 cm long x 6.5 cm diameter

The pith cast of Calamites is the most common plant steinkern. As a Calamites tree matured the center of the stem (pith) became hollow, developing into a tube-shaped air cavity. The pith cast preserves an impression of the pith cavities outside surface, which represents the inside vascular and cortex tissue (Taylor, Taylor & Kring, 2009, p. 23).

 

Taylor, T.N., Taylor E.L. & Krings, M. (2009). Paleobotany: The Biology and Evolution of Fossil Plants [2nd Ed]. New York: Academic Press.


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