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Psyscope visual basic10/3/2023 Fossils are known from the Cenomanian onwards. During the Paleocene and Eocene, extensive forests of Metasequoia occurred as far north as Strathcona Fiord on Ellesmere Island and sites on Axel Heiberg Island (northern Canada) at around 80° N latitude. Metasequoia was likely deciduous by this time. Given that the high latitudes in this period were warm and tropical, it is hypothesized that the deciduous trait evolved in response to the unusual light availability patterns, not to major seasonal variations in temperature. During three months in the summer, the sun would shine continuously, while three months of the winter would be complete darkness. It is also hypothesized that the change from evergreen to deciduous trait occurred before colonizing the high latitudes and was the reason Metasequoia was dominant in the north. Large petrified trunks and stumps of the extinct Metasequoia occidentalis (sometimes identified as Sequoia occidentalis) also make up the major portion of Tertiary fossil plant material in the badlands of western North Dakota. Before its discovery, the taxon was believed to have become extinct during the Miocene when it was discovered extant, it was heralded as a " living fossil".ĭawn redwood foliage - note opposite arrangement The trees are well known from late Cretaceous to Miocene strata, but no fossils are known after that. The bark and foliage are similar to Sequoia, but Metasequoia is deciduous like Taxodium distichum (bald cypress), and, similarly, older specimens form wide buttresses on the lower trunk. It is a fast-growing tree to 130–150 feet (40–45 m) tall and 6 feet (2 m) in trunk diameter in cultivation so far (with the potential to grow even higher). The leaves are opposite, 0.4-1.25 inches (1–3 cm) long, and bright fresh green, turning foxy red-brown in fall. The pollen cones are 0.25 inch (6 mm) long, produced on long spikes in early spring they are only produced on trees growing in regions with hot summers. The cones are globose to ovoid, 0.6-1.0 inches (1.5-2.5 cm) in diameter with 16–28 scales, arranged in opposite pairs in four rows, each pair at right angles to the adjacent pair they mature in about 8–9 months after pollination. History Įocene ( Ypresian) age M. occidentalis branchlet Metasequoia has experienced morphological stasis for the past 65 million years: the modern Metasequoia glyptostroboides appears identical to its late Cretaceous ancestors. The fossil of this genus was discovered by Shigeru Miki in 1939. In 1941, Miki published the description of the fossil plant which he gave the name "Metasequoia". In the winter of the same year, a Chinese botanist Toh Gan (干铎)discovered an unusual big tree in Modaoxi (磨刀溪 presently, Moudao (谋道), in Lichuan County, Hubei ). The locals called this tree shui-sha (水桫). Because it was winter, the tree already lost all its leaves, so no specimens were collected by Mr. Zhan Wang (王战) visited Modaoxi and collected living specimens.
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