A probable pteridosperm with eremopterid foliage from the Allegheny Group of northern Pennsylvania

Compressed fossilized foliage most comparable to that of Eremopteris zamioides (Bertrand) Kidston occurs in shale associated with coal in the Allegheny Group in northern Pennsylvania. In association with this foliage are abundant samaropsid seeds and small, apparently microsporangiate organs. Although close proximity of disconnected plant parts as fossils is not evidence in itself that these plant parts were originally connected, it is tempting to believe that these leaves, seeds, and microsporangia were parts of the same species. Furthermore, there have been a number of previous reports associating samaropsid seeds with Eremopteris. Additional frondlike structures with the same basic construction as the vegetative eremopterid leaves have been found; these offer information concerning the possible mode of attachment of the fertile organs

The Shoot Apex of Callistophyton poroxyloides

285-299http://deepblue.lib.umich.edu/bitstream/2027.42/48300/2/ID140.pd

A new Triassic cycad and its phyletic implications

Upper Triassic beds in North Carolina yield excellently preserved compressions of ferns, cycadophytes and conifers. Among the cycadophyte remains are leaves comparable to those of the genus Pseudoctenis attached to a slender, elongated stem fragment. Other stem remains show bases of petioles with a similar arrangement. Cuticular analysis of laminae, rachises and stem surfaces suggests the existence of a member of the Cycadales with loosely arranged pinnately compound fronds on a slender stem, with cataphylls and terminal cones. Although Cycadales probably originated before the Triassic, the growth habit of only a very small number of Triassic members is known. This discovery is significant in allowing the reconstruction of one of the oldest members of the order and presents evidence that its growth habit is unlike that of later Cycadales. The slender stem and loosely spaced compound leaves point to a pteridosperm ancestry

Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/1/nph14700_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/2/nph14700.pd

A Middle Triassic flora from the Cacheuta Formation, Minas de Petroleo, Argentina

Volume: 10Start Page: 564End Page: 58