![]() ![]() The most massive seed cones may weigh up to 95 pounds, and are produced by species of Lepidozamia and Encephalartos. Cycad cones can reach 3 feet in length, the largest of all living cone-bearing plants. These plants were so numerous in Mesozoic times (65 to 230 million years ago) that this era is often called the "Age of Cycads and Dinosaurs." Cycads are dioecious species with pollen cones and seed cones produced on separate male and female individuals. Perhaps the most remarkable of all seed plants that flourished during the days of the dinosaurs are the cycads. Many conifers and broad-leaf angiosperms have been identified from this fossil-rich shale (note other leaves in photo). The soft brown shale is from ancient Miocene lake bed sediments made from layers of volcanic ash and silt. In fact the genus Metasequoia was described first as a fossil by a Japanese paleobotanist Shigeru Miki in 1939 but just a few years later several Chinese. Close examination of the needles reveals that this extinct species is not a Sequoia, but is remarkably similar to our present-day Metasequoia. This lovely deciduous conifer once coexisted with dinosaurs in North America during the Cretaceous Period 90 million years ago.Ī 25 million-year-old leaf of dawn redwood ( Metasequoia) from the John Day Fossil Beds National Monument in Eastern Oregon. The foliage and cones of the dawn redwood ( Metasequoia glyptostroboides) superficially resemble the California coast redwood ( Sequoia sempervirens). Metasequoia glyptostroboides was first known only as fossils from the late. Indeed this "living fossil" was brought back to its ancestral home. It is the sole living species of the genus Metasequoia, and one of three. All North American plantings of this superb cone-bearing tree came from the seeds (and their progeny) originally collected in China. The seed cones and foliage of the dawn redwood superficially resemble our California coast redwood ( Sequoia sempervirens), except that the dawn redwood is deciduous and loses its leaves during the winter months. It has been estimated that the relict forest in China may have been surviving in this remote primeval valley for countless thousands of years. Some of the fossils date back nearly 90 million years, from a time when the climate was much more humid than today. Leaf imprints and petrified wood of ancestral dawn redwoods resembling the present-day species have been found in Cretaceous deposits throughout North America. Thus within 18 months Metasequoia had been both recognised and resurrected. Ralph Chaney of the University of California, Berkeley led a 10,000 mile expedition up the Yangtze River and across three mountain ranges to a lush, fog-shrouded valley where a thousand dawn redwoods were growing. He did not realise it at the time, but within a few years the discovery would be heralded around the world as a ‘living fossil’: Wang had discovered living trees of Miki’s fossil genus. ![]() The genus Metasequoia was first described from fossil material by the Japanese paleobotanist Shigeru Miki in 1941. ![]() Another ancient cone-bearing tree that was thought to be extinct but was later discovered growing in a remote valley of Central China is the dawn redwood ( Metasequoia glyptostroboides). ![]()
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