Temporal range: Middle Devonian
Wattieza was a genus of prehistoric trees that existed in the mid-Devonian that belong to the cladoxylopsids, close relatives of the modern ferns and horsetails. The 2005 (publicly revealed in 2007) discovery in Schoharie County, New York, of fossils from the Middle Devonian about 385 million years ago united the crown of Wattieza to a root and trunk known since 1870. The fossilized grove of "Gilboa stumps" discovered at Gilboa, New York, were described as Eospermatopteris, though the complete plant remained unknown. These fossils have been described as the earliest known trees, standing 8 m (26 ft) or more tall, resembling the unrelated modern tree fern.
English geologist and palaeobotanist Chris Berry described Wattieza casasii in 2000 from fossil branches collected from Middle Devonian strata—green mudstones and shales close to the base of the Campo Chico Formation, Givetian—in Cano Colorado, Perija Range, Venezuela.
- Stein, W. E., F. Mannolini, L. V. Hernick, E. Landling, and C. M. Berry. 2007. "Giant cladoxylopsid trees resolve the enigma of the Earth's earliest forest stumps at Gilboa", Nature (19 April 2007) 446:904-907.
- Meyer-berthaud, B.; Decombeix, A.L. (2007). "Palaeobotany: A tree without leaves". Nature. 446 (7138): 861–862. arXiv:0704.2554. doi:10.1038/446861a. PMID 17443169. S2CID 4324196.
- Berry, Chris (2009). "The Middle Devonian plant collections of Francois Stockmans reconsidered". Geologica Belgica. 12 (1–2): 25–30.
- Berry, CM (1 October 2000). "A reconsideration of Wattieza Stockmans (here attributed to Cladoxylopsida) based on a new species from the Devonian of Venezuela". Review of Palaeobotany and Palynology. 112 (1–3): 125–146. doi:10.1016/s0034-6667(00)00038-5. ISSN 0034-6667. PMID 11042329.
- Paleobiology Database accessed 19 April 2007
- "Oldest tree had fronds, not leaves". Article on CNN.com
- (Cosmos) Michelle Carr, "Wattieza is world's oldest tree" 19 April 2007