Eospermatopteris †

Eospermatopteris is a form taxon that represents the earliest known tree-like plants from the geologic record, found in areas of New York State and Europe. Also known as the Gilboa Trees, the fossils exist as mostly stump casts and are usually large and bulb-shaped with roots radiating from the stump. They frequently lack any aerial portions, but localities in the late 2000s produced complete specimens, indicating a height of 8 m. The upper portions, called Wattieza, were large, leafless, photosynthetic branch systems. It is unknown whether this plant possessed wood, and it appears that they were supported through a meshwork vascular system but probably weakly constructed.

The name "Eospermatopteris" translates to "dawn seed fern", because early researchers erroneously interpreted this plant as a pteridosperm. Fossils of progymnosperms from the same locality were used to assemble the upper portions of the plant, creating the classic reconstruction of Eospermatopteris (Goldring 1924). To date, there have never been seed ferns found at the locality. Due to the work in 1990s to the present day, this plant is much better known as a Cladoxylopsid fern.

Form and Ecology

These plants had the capacity to live in several different ecological settings rather than being restricted to wetter environments (Stein et al. 2019)
These plants were probably "weedy in habit, relatively fast growing", and able to disperse to a variety of locations in the ancient forest as chance, local disturbance, or openings in the forest canopy might have allowed (Stein et al. 2019)

Stems

Known for large stump bases up to 1 m in diameter
- Findings suggest that the plant was about 8 m high
In cross-section, the stumps possessed a central pith, cortex, and in between a ring of vascular strands with primary xylem and radially aligned cells.
- The radially aligned cells may be secondary xylem
- Their upright habit includes extensive augmentation of tissues by means of extended lateral meristem development, but limited sclerified tissues (Xu et al. 2017)
The xylem system accommodates expansion by tearing of individual strand interconnections during secondary development
This mode of growth seems indeterminate, capable of producing trees of large size, and despite some unique features, invites comparison with secondary development in some living monocots

Leaves

Leafless "foliage"; system of photosynthetic axes that were non-laminate
A crown of short erect branches, similar to Wattieza, were attached to the top of stumps
The branches were regularly shed and replaced by new branches at the top of the plant

Roots

- The bulbous base had adventitious roots emerging below the soil.
- Roots traverse the length of the stem, and emerge to act as guy wires for support
- The roots are strap-like and unbranched in appearance

Classification

└Cladoxylopsida †

└Pseudosporochnales †

Geologic Age

Givetian
The earliest known tree-like fossil in the geologic record
Oldest fossils from 390 Ma in southwest England (Davies et al., 2024), followed by the Catskills of New York at 385 Ma (Stein et al. 2019)

Above: Reconstructions of Eospermatopteris-Wattieza

Above: reconstruction of Eospermatopteris with progymnosperm vines at the Gilboa site during the Givetian

Above: Eospermatopteris lower trunk

Above: the underside of a Eospermatopteris trunk

Above: Eospermatopteris upper trunk

Above: Eospermatopteris distal branches

Above: the bottom of an Eospermatopteris stump showing radiating, strap-like roots

Above: "crater" where an individual of Eospermatopteris would have grown

Above: Reconstruction of the Gilboa forest from the Middle Devonian of New York State

Above: Reconstruction of the ancient forest by Anna Kotler

Above: Discovery of an Eospermatopteris stump by construction worker building the Gilboa dam in the 1920s

Additional Resources

The fossil forests of Gilboa (Palaeocast Ep.4)
Video showing excavation of the Eospermatopteris forest during reconstruction of the Gilboa dam (narrated by Chris Berry, Ph.D.)
Video discussing the discovery of an Eospermatopteris forests during the late 2000s (Binghamton University 2012)
Discovery of 385 million year old forests emerged earlier than believed (Binghamton University 2019)
State Paleontologist, Lisa Amati Ph.D., details the history behind the discovery and study of two Devonian fossil forests in New York State (NY State Museum 2020)

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