Earth’s Original Land Tree Plant

Was the “Calamite” the first tree-like plant to grow on land? Many scientists believe so. It grew as high as 100 feet, towering above its counterparts in the earlier periods of its lengthy lifespan, which began some whopping 400 million years ago during the Devonian Period.

Annularia Leaf Imprint Trace Fossil of Prehistoric Calamite Tree

The trunk was a woody hollow tube, lacking true bark. The leaves were primitive and needle like, arranged in whorls around a stem.

Trace Fossil Imprint of Prehistoric Calamite Tree Stem

The Calamite thrived in the hot swamp tropics of the past, particularly during the Pennsylvanian Period around 300 mya. Many of their fossils have been found worldwide including, USA, China, Canada, South America and Europe.

Internal and External Imprint Fossil of Calamite Tree Stem

These amazing fossils were found in Sebastian County, Arkansas in an old coal strip mine in 1993 by Michael A. Whitkanack, who donated them to my classroom. They are actually the imprints of the Calamite’s leaves and stems which scientists refer to as trace fossils.

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Prehistoric Calamite (Earth’s First Tree-Like Land Plant) Rendition Drawing

 CLASSIFICATION

Scientific Name: Calamite Common Name: Horsetail / Wiskfern

Kingdom: Plantae

Division: Pteridophyta (Ferns, reproduce by spores)

Class: Sphenopsida or Equisetopsida (means ribbed, vertical jointed stem; bamboo like in appearance)

Order: Equisetales

Family: Calamitaceae

Genus:  (STEM) Calamite (LEAF) Annularia

Special Note: The Calamite may look familiar to some, as their modern descendants are the “horsetails” of today, growing in open fields and edges of woodlands, but only reaching a few feet tall. See photo below

Equisetopsida

The “horsetail” or Equisetum is an amazing living fossil related to the Calamites, being the only surviving genus from the entire class of Equisetopsida. For over one hundred million years, the Equisetopsidas were much more diverse and dominated the understory of the late Paleozoic forests. Through the millenniums, they decomposed layer by layer, transforming into the sunken coal deposits of today.

Comparing Neuropteris and Pecopteris Fossil Leaves and Their Trees, Medullosa and Psaronius

Neuropteris Fossil Leaf Imprint

Extinct Neuopteris leaves are associated with the seed fern tree called Medullosa, an ancestor of the flowering plant group. They flourished during the hot swamps of the Carboniferous through the Permian time slots about 360 to 250 million years ago. When Earth’s climate turned colder, it contributed to their final disappearance.

One way to tell the difference between Neuropteris and Pecopteris leaf fossil imprints is by examining the mid-vein of their leaflets. In Neuropteris, the vein stops midway up the leaflet and splits into several fine veins, whereas the mid-vein in Pecopteris extends up to the tip. Neuropteris leaflets are more blunt tipped and attach by a single stem as opposed by the entire base, as with Pecopteris. Also, Neuropteris has an overall heart shape.

NEUROPTERIS LEAF CLASSIFICATION

Kingdom: Plantae

Division: Tracheophyta (vascular plants with system of transporting nutrients and liquids)

Class: Gymnosperm (means bare seeds – today’s examples i.e. conifers, cyads, ginkgo)

Order: Pteridospermales (extinct group of seed ferns which bore seeds on leaves)

Family: Medullosales (plants with complex pollen organs and large fronds)

Genera: Neuropteris (given name of foliage)

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Prehistoric Medullosa Seed Fern Tree Rendition Drawing

Medullosa Seed Fern tree associated with Neuropteris was a medium sized, seed fern tree reaching about 33 feet (10 meters) tall. It really was not a true fern because it produced seeds, instead of spores. It only resembled fern trees and grew during the same era as the true fern trees, for example, Psaronius associated with the Pecopteris leaves. The leaves of Medullosa had many leaflets attached to a stem and could grow quite large, as much as 10 feet (3 meters) long.

MEDULLOSA SEED FERN TREE CLASSIFICATION

Kingdom: Plantae

Clade: Traceophytes (Large group of vascular plants with transport system for nutrients and fluids)

Division: Pteridosperm(aphyta) (Extinct group of seed bearing plants)

Order: Medullosales ((plants with complex pollen organs and large fronds)

Family: Neurodontopteridaceae (Neuropteris Leaf)

Genus: Medullosa

Explanation of Pecopteris on following page . . .