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Angela Gilmour Image 5 Detail Archaeopteris i,  Lycopsids i Cladoxylopsida and Aneurophyte

Shadow Forests


Lord Mayor's Pavilion, Ireland

In association with Sample Studios

March 16th to April 23rd, 2022

To coincide with National Tree Week and International Earth Day

Mid-Devonian Trees


"The origin of trees and forests in the Mid Devonian (393–383 Ma) was a turning point in Earth’s history, marking permanent changes to terrestrial ecology, geochemical cycles, atmospheric CO2 levels, and climate." Drs. Stein, Berry, et. al.

Archaeopteris, Lycopods, Cladoxylopsids and Aneurophytes (this is the order above [with an aneurophyte wrapped around a clodoxylopsid]) were among the very first trees. These trees were taller than the shrubby and ground-hugging plant life that preceded them. As they grew taller during the middle Devonian period, the trees pulled significantly higher amounts of CO2 out of the atmosphere and began the creation of a habitable planet. 


Archaeopteris trees hold the closest relation to modern trees. They were similar to conifers with complex and deep roots. From these roots grew rootlets which may have connected with other plants and trees. These were the first trees to grow branches that did not shed quickly as the trees grew. From these branches grew fern-like leafy fronds which did shed continuously. 


Unlike most modern trees, archaeopteris reproduced from spores instead of seeds.



Lycopsids dominated during the later Paleozoic Era. They survived from the Devonian period and remained until the Permian period. Their remains formed the majority of Earth’s coal beds which fueled the Industrial Revolution and beyond. Lycopsids did not have broad leaves, rather they had microphylls with narrow, sometimes divided lamina supplied by an unbranched vein, and they reproduced by emitting spores. 



Cladoxylopsids are considered to be the first trees. They were remarkable in many ways, in particular the base of the tree was hollow, with the wood as a ring of separate strands rather than a solid trunk, and they ripped themselves and their connective tissue apart to grow taller, seeking the sun. Eventually cladoxylopsids would collapse onto themselves. This process of growth was unique to cladoxylopsida trees.


Cladoxylopsids did not have flat leaves because the high CO2 level in Earth's atmosphere would have burned them. Instead, they had frond-type branches with twiggy appendages containing photosynthetic organs. They were therefore able to withstand the high CO2 levels. These branches shed constantly and the forest floor was littered with their remains. They reproduced by emitting spores.

There are no known living relatives of cladoxylopsids.



Aneurophytes had woody rhizomes that grew along the forest floor, leaning and climbing up against other trees in what is believed to be a symbiotic relationship. Similar to cladoxylopsids, aneurophytes did not have laminate leaves, but photosynthetic twiggy appendages and reproduced by emitting spores. 

The artists are extremely grateful for the generous scientific support provided to this exhibition by: Christopher Berry, Ph.D., University of Cardiff (Paleobotanist); William Stein, Ph.D., State University of New York, Binghamton, Professor Emeritus (Paleobotanist)

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