Name: Calamostachys
schimper
Division:
Equisetophyta; Class: Equisetopsida; Order: Equisetales; Family: Calamitaceae
Geological
Time: Carboniferous Westphalian C, (~310 million years old)
Size: 38
mm long by 8 mm wide Matrix: 60 mm by 43 mm
Fossil Site:
Lower Block Shale, Crawford County, Indiana
This
is a cone (or reproductive organ) of a member of the extinct genus
Calamites. Whorls of small leaflets are arranged concentrically
around a thin stem and are called Annularia or Asterophyllites.
Calamites itself is the name originally given to a stem section,
but now applies to the entire plant. These plants thumid to hrived
in wet habitats such as along rivers and lake shores. Entire cones
are found quite infrequently, making this a most unusual fossil
with the bracts and sporangia quite evident. They are related to
the sphenophytes such as the extant horsetail Equisetum.
The
genus Calamites is placed in the plant division Equisetophyta, which
was previously known as Sphenophyta), and in the family Calamitaceae.
Calamites became extinct in the Lower Permian.
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