Lyssoxylon grigsbyi, a Cycad Trunk from the Upper Triassic of Arizona and New Mexico
Gould RE. 1971. Lyssoxylon grigsbyi, a Cycad Trunk from the Upper Triassic of Arizona and New Mexico. American Journal of Botany. 58(3):239-248
Lyssoxylon grigsbyi Daugherty, a petrified stem with petiole bases, was originally described from the Upper Triassic Chinle Formation of Arizona and considered to be a member of the Williamsoniaceae. Investigation of additional material from a similar horizon in New Mexico, together with re-examination of preparations of the holotype, suggest that the plant, with its monoxylic stele, girdling leaf traces, and bicelled epidermal hairs is a true cycad. Cells of the New Mexico specimens contain structures interpreted as preserved nuclei.
- Type
- Journal Article
- Authors
- Gould, R
- Units
- PEFO
- Keywords
- Cycads Fossil, Lyssoxylon grigsbyi, PALEOBIB, Paleontology, Trees Fossil