Museum, University of Nebraska State


Date of this Version



Published in Museum Notes (August 1994) No. 88: 6 p.


The plant fossils found in shales and sandstones of the late Cretaceous age Dakota Group in Nebraska and Kansas figure prominently in the "drama tis plantae" of the long-running and still unsolved mystery of the origin of flowering plants (angiosperms). This mystery has many fans because almost all of the plants that humans depend on for food and shelter are angiosperms; half of the calories in the world's diet come from the grass family alone. The Dakota fossils were discovered by western science more than one hundred years ago during the early stages of geological exploration of the western territories. The discovery of 100 million year old, late-Cretaceous leaves that had the shapes, sizes, and outlines of modern trees such as sassafras (Sassafras), magnolia (Magnolia), rubber tree (Ficus), and willow (Salix) astounded nineteenth century scientists. Although they had some reservations about the identifications, these early paleobotanists assigned many of the leaves to modern genera. These almost modern flowering plant leaves seemed to appear suddenly in the mid-Cretaceous and, with amazing geological rapidity (10 - 20 million years), preempted the leading role in the world's flora. All reports of flowering plant fossils at or before the beginning of the Cretaceous, 138 million years ago, are doubtful. However, by the end of the Cretaceous, 9 out of every 10 vascular plants were angiosperms. (Now there are 250 species of flowering plants for every species of gymnosperm.) There was no geological warning of this change in the cast of vegetational players, no prominent understudy (or understory) roles that signaled that flowering plants were to be the stars of the future. These upstarts replaced the cast of conifers, ginkgoes, seed ferns, cycads, cycadeoids (all gymnosperms), and ferns that had composed the floristic company for the previous 150 million years. Charles Darwin called the questions of when and where flowering plants arose and why and how they so quickly stole the limelight in the plant part of the evolutionary stage an "abominable mystery". The leaf fossils of the Dakota Group in Nebraska and Kansas figured prominently in this mystery because they provided one of the oldest records of a flora in which flowering plants out-numbered the ferns, conifers, and cycads.