Fossils/Plants

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Main article: Fossils

Organisms in the kingdom Plantae are said to be plants. Plants a majority of their energy through photosynthesis, and many of them reproduce through seeds (though there are some such as mosses and ferns that reproduce via spores). Many plant fossils will be in the form of leaves, though some fossils may feature the bark or a branch of a tree. Lepidodendron is one such fossil that is frequently identified by its bark as opposed to its leaves.

Flowering Plants (Phylum Anthophyta)


Genus Acer (Maple)
Acer.jpg
Common Names Maple trees
Physical Description Maple leaves are palmate, with each of the five lobes spreading from the base of the leaf. Compared to a sycamore (Platanus) leaf, the lobes tend to be more rounded and less spread out. The way the leaf attaches to the stem is also different - in the sycamore, the leaf simply fans out from the stem but in the maple the lobes tend to have more of a curve instead of extending straight from a point. Another difference between the two genera is the edges of the leaves - many sycamore leaves will have serrated or otherwise spiked edges, and this is less common (though not impossible) in maples. Despite many common differences, some specimen are very difficult to differentiate on leaves alone. One of the most reliable ways to differentiate the two is that sycamore leaves have three main veins that branch into the two side veins, while the main veins in maple leaves are separate.
Fossil Range Paleocene to Recent
Mode of Life/Habitat Modern maple trees are very hardy, and can grow in a wide variety of conditions. However, they thrive in cool and wet conditions (which is why they are so prevalent in the north and northeast parts of the globe). Maple trees can also survive in a variety of light conditions, with maples in cool climates preferring full sun. However, in warm climates they prefer partial shade as too much sun exposure can result in wilting.
Adaptations over Time As maple trees are typically deciduous, they drop their leaves in the wintertime which allows them to remain dormant and conserve energy. Maple tree seeds also have wing-like structures, allowing the seeds to travel far from predators or other harm. Many of the root systems are typically dense and fibrous, inhibiting the growth of other vegetation underneath them. This also allows the roots to spread out, gathering water more efficiently.
Distribution Many extant species are found in Asia, though some are also found in Europe, North America, and northern Africa. Typically, these species are only found in the northern hemisphere (though there are some exceptions). Fossils of this genus seem to follow the same distribution, being found primarily in the northern hemisphere.
Additional Information Acer is an extant genus of angiosperms, also known as flowering plants. Most maples are trees growing to a height of 10–45 m (33–148 ft). Others are shrubs less than 10 meters tall with a number of small trunks originating at ground level. Most species are deciduous, and many are renowned for their autumn leaf color, but a few in southern Asia and the Mediterranean region are evergreen. Most are shade-tolerant when young and are often riparian, understory, or pioneer species rather than climax overstory trees. However, there are a few exceptions (such as the sugar maple).
Taxonomy
Family: Sapindaceae
Subfamily: Hippocastanoideae


Genus Populus (Aspen & Poplar)
Populus.jpeg
Additional Information Populus is an extant genus of deciduous tree-like flowering plants (aspen trees, poplar trees). The genus has a large genetic diversity, and can grow from 15–50 m (49–164 ft) tall, with trunks up to 2.5 m (8 ft 2 in) in diameter. Populus is indigenous to much of the northern hemisphere.


Genus Platanus (Sycamore)
Platanus.jpg
Additional Information Platanus is an extant genus of sycamores (also known as plane trees). Most species of Platanus are between 100 and 150 feet tall. Most species of Platanus are deciduous, but Platanus Kerrii is coniferous. Most plane trees grow in areas of high water content, such as a wetland. They have, however, been found to be drought-tolerant. Members of the genus Platanus have existed since the late Cretaceous. Science Olympiad competitors commonly mistake Platanus with Acer, a similar tree species. One surefire way to tell the two apart would be to look at the way the veins of the leaves branch. All Platanus leaves will have 3 main veins that branch into two separate veins, and Acer does not have these branching veins.

Ginkgos (Phylum Ginkgophyta)


Genus Ginkgo
Ginkgo.jpg
Additional Information Ginkgo is a genus of highly unusual non-flowering plants. The scientific name is also used as the English name. The rate of evolution within the genus has been slow, and almost all its species had become extinct by the end of the Pliocene; the exception is the sole living species, Ginkgo Biloba, which is only found in the wild in China, but is cultivated across the world. Ginkgo preferred more watery environments.

Club Mosses (Phylum Lycopodiophyta)


Genus Lepidodendron (scale tree)
Lepidodendron.jpg
Additional Information Lepidodendron (common term: Scale Trees) is an extinct genus of tree-like vascular plants. They came about in the early Carboniferous period, and later went extinct in the late Triassic period. Most species of Lepidodendron would live for 10-15 years. Lepidodendron displayed constant dichotomy, meaning that whenever the tree splits in to 2 branches, those branches would be evenly sized. Fossils of Lepidodendron have commonly been found in North America, Europe, and Asia.

Conifers (Phylum Pinophyta)


Genus Metasequoia
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Additional Information Metasequoia (dawn redwoods) is a deciduous tree, which is known to grow relatively quickly. Certain species of Metasequia have been known to reach heights of above 165 feet, which is actually among the shortest redwoods in the world. Metasequoia is extant, and has existed since the late Cretaceous period. The extant species of Metasequoia, Metasequoia Glyptostroboides is indigenous to China. Metasequoia has not evolved at all in the last 65 million years, they are seen today exactly as they were 65 million years ago.

Horsetails (Phylum Sphenophyta)


Genus Calamites
Calamites.jpg


Genus Annularia
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Additional Information Annularia is a form taxon, applied to fossil foliage belonging to extinct plants of the genus Calamites in the order Equisetales. Annularia leaves are arranged in whorls of between 8-15 leaves. Its shape is quite variable, being oval in Annularia sphenophylloides and semilinear in Annularia radiata, but they are always flat and of varying lengths. Annularia only existed in the Carboniferous period, although they could've possibly existed in the Permian period.

Seed Ferns (Phylum Pteridospermatophyta)


Genus Glossopteris
Glossopteris.jpeg
Additional Information Glossopteris is the largest genus of seed ferns (Order Glossopteridales). Glossopteris was a woody, seed-bearing shrub or tree, some reaching 30 meters tall. It is unknown if Glossopteris was monoecious or dioecious. Glossopteris only existed in the Permian. It is also very important to the theory of past supercontinents.

True Ferns (Phylum Pteridophyta)


Genus Psaronius


Genus Pecopteris
Pecopteris.jpg
Fossil Range Late Devonian to Permian
Mode of Life/Habitat Photosynthesizer
Distribution South America, North America, Europe, Parts of Asia
Additional Information Pecopteris is a very common form genus of leaves. Most Pecopteris leaves and fronds are associated with the marattialean tree fern Psaronius. Pecopteris first appeared in the Devonian period, but flourished in the Carboniferous, especially the Pennsylvanian. Plants bearing these leaves became extinct in the Permian period. It is the only true fern that humans know about.
Taxonomy
PecopterisTaxonomy.png