The Caytoniales (Figs. 1-2) are an extinct order of seed plants known from fossils collected throughout the Mesozoic Era, around 252 to 66 million years ago.[2][3][4] They are regarded as seed ferns because they are seed-bearing plants with fern-like leaves.[4] Although at one time considered angiosperms because of their berry-like cupules,[5] that hypothesis was later disproven.[6] Nevertheless, some authorities consider them likely ancestors or close relatives of angiosperms.[7] The origin of angiosperms remains unclear, and they cannot be linked with any known seed plants groups with certainty.
^Niklas, Karl J. (1997). The Evolutionary Biology of Plants. University Of Chicago Press. p. 470. ISBN978-0-226-58083-8.
^National Academy of Sciences (2000). Ayala, Francisco J.; Fitch, Walter M.; Clegg, Michael T. (eds.). Variation and Evolution in Plants and Microorganisms: Toward a New Synthesis 50 Years after Stebbins. National Academies Press. p. 352. ISBN978-0-309-07099-7.
^ abArnold, Chester (1947). An Introduction To Paleobotany. Miller Press. p. 428. ISBN978-1-4067-1861-4.