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Calamites Stem (Arthropitys)
Arborescent
Horsetail
Calamitean Stem Arthropitys sp.
Bieland, Maranhao Province, Brazil
Pedra de Fogo Formation
Permian
10.5 cm x 8 cm |
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The name Calamites was intially given to pith casts. The genus now encompasses various preservation modes of stems, pith, and the central canal. Possibly the most common petrified calamitean stem type is Arthropitys (Taylor, Taylor, and Krings, 2009, p. 345). The
stem of the Arthropitys specimen pictured above 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 Arthropitys possessed air spaces called valecular canals. |
Arborescent
Horsetail
Arthropitys sp.
Bieland, Maranhao Province, Brazil
Pedra de Fogo Formation
Permian
11.5 cm x 10 cm
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The
permineralized Calamites stem (Arthropitys) 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
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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