中国科学院南京地质古生物研究所机构知识库

Tricalycites Hollick is a distinctive winged propagule that has served as a stratigraphic marker in North American Cretaceous floras. However, its affinities have long been uncertain since the original description of this genus in 1895. Our recent re-examination of specimens from major museum collections and from recent fieldwork has allowed for a revised concept of the morphology and the addition of new details of epidermal anatomy. Twenty three specimens were studied from numerous sites, ranging over a broad area of eastern North America including New Jersey, New York, Massachusetts, Rhode Island, Alabama, and Texas. Tricalycites disseminules have often been called winged fruits, but we cannot eliminate the possibility of them being gymnospermous seeds with a wing derived from an associated envelope or cupule. The type species, T. papyraceus, was previously described by Newberry as having one wing with three lobes or three wings, but we observed only one wing with three prominent lobes. Cuticles of Tricalycites were examined for the first time. The wings lack trichome bases and have paracytic to tetracytic stomata. The new observations facilitate a revised circumscription of the genus Tricalycites but still leave the affinities of this plant open for discussion. (C) 2020 Elsevier Ltd. All rights reserved.