The discovery, made on Bathurst Island in the Northwest Territories about 800 miles from the North Pole, shows vascular plants were more complex at that time than paleontologists previously believed and is significant for that reason, the UNC researcher said.
These are not the earliest vascular plants ever found, but they are the earliest ever found of this size, complexity and degree of diversification, said Dr. Patricia G. Gensel, professor of biology at UNC. They look something like medium-sized grasses, except that they branch.
The discovery adds to the sparse record of early land plants known from North America, Gensel said. Previously, most information on ancient plants has been based on fossils from Wales, Venezuela and China.
A report about the findings appears in the June issue of the American Journal of Botany. Besides Gensel, authors are UNC graduate student Michele E. Kotyk, Dr. James F. Basinger, professor of geology at the University of Saskatchewan, and Dr. Tim A. de Freitas, a Calgary, Canada geologist working for Nexen Inc.
Bits and pieces of the earliest known land plants date back almost 500 million years to the Ordovician Period, and their fragmentary remains indicate the plants were related to liverworts that exist today, Gensel said. The earliest vascular plants -- ones with water-conducting tissues -- so far are known to date back about 425 million years. Sparsely branched, they were about an eighth of an inch tall and grew a few reproductive bodies known as sporangia on their branches.
By contrast, the new plants, which lived only a few million years later, would have stood four or more inches tall, bore many branches with dense rows of sporangia and probably grew in clusters, she said. They more closely resembled mu
Contact: David Williamson
University of North Carolina at Chapel Hill