Thuja occidentalis Linnaeus, 1753 - eastern arbor vitae tree in Virginia, USA. (13 May 2016)
Plants are multicellular, photosynthesizing eucaryotes. Most species occupy terrestrial environments, but they also occur in freshwater and saltwater aquatic environments. The oldest known land plants in the fossil record are Ordovician to Silurian. Land plant body fossils are known in Silurian sedimentary rocks - they are small and simple plants (e.g., Cooksonia). Fossil root traces in paleosol horizons are known in the Ordovician. During the Devonian, the first trees and forests appeared. Earth's initial forestation event occurred during the Middle to Late Paleozoic. Earth's continents have been partly to mostly covered with forests ever since the Late Devonian. Occasional mass extinction events temporarily removed much of Earth's plant ecosystems - this occurred at the Permian-Triassic boundary (251 million years ago) and the Cretaceous-Tertiary boundary (65 million years ago).
The most conspicuous group of living plants is the angiosperms, the flowering plants. They first unambiguously appeared in the fossil record during the Cretaceous. They quickly dominated Earth's terrestrial ecosystems, and have dominated ever since. This domination was due to the evolutionary success of flowers, which are structures that greatly aid angiosperm reproduction.
The eastern arbor vitae, Thuja occidentalis, is a gymnosperm - it is a type of cypress. This slow-growing, long-lived tree is native to eastern North America. It occurs in parts of southeastern Canada, New England, the Great Lakes area, and in portions of the Appalachian Mountains. Living and dead individuals have been found that are over well over 1,000 years old.
From park signage:
"Before dying in 1980, this more than 1600 year old specimen of the arbor vitae tree was the oldest and largest known in the world. Its diameter measures 56 inches. Depending on climatic conditions that determine its growth rate, the arbor vitae increases in diameter about one inch every thirty years."
Classification: Plantae, Spermatophyta, Pinophyta, Pinopsida, Pinales, Cupressaceae
Locality: trailside forest along Cascade Creek, Natural Bridge State Park, southern Rockbridge County, west-central Virginia, USA
------------------
Info. at:
en.wikipedia.org/wiki/Thuja_occidentalis
