Editing Florissant Formation (section)

===Paleoflora===
[[File:Florissant Fossil Beds National Monument FLFO1237.jpg|thumb|Fossilised leaf preserved in fine detail]]There is a large diversity of plants in the beds of the Florissant Formation, ranging from large redwoods to microscopic pollen. The petrified forest is one of the main tourist attractions at the monument with an estimated 30 preserved stumps. They are among the largest petrified stumps in the world.{{citation needed|date=May 2021}}  The majority of the stumps have been identified as belonging to ''[[Sequoia affinis]]'', a close relative of the modern [[Sequoia sempervirens|coast redwood]] (''S. sempervirens'').<ref>{{Cite web |last=Florissant |first=Mailing Address: P. O. Box 185 |last2=Us |first2=CO 80816 Phone: 719 748-3253 Contact |title=Sequoia affinis Reconconstruction - Florissant Fossil Beds National Monument (U.S. National Park Service) |url=https://www.nps.gov/flfo/learn/nature/sequoia-affinis.htm |access-date=2022-05-05 |website=www.nps.gov |language=en}}</ref> These trees could have been as tall as {{convert|60|m|ft|abbr=on}} until they were killed by lahars suffocating the oxygen supply to their roots. [[Dendrochronology|Dendrochronological examination]] of the tree rings has resulted in estimated ages of 500–700 years old when the trees were killed and buried. Some of the stumps belong to [[angiosperms]].<ref name="book"/>
 
The Florissant Formation is also known for its fossilized leaves and the impressions they made. There are also specimens of fruits, seeds, cones, and flowers, which are all preserved in the paper shales of the formation. Most of the leaves come from trees and shrubs. Angiosperms are the dominant paleoflora, but there are also conifers present.<ref name="book"/>

Some of the cones, foliage, and pollen have been identified as coming from the sequoias. There are distinct differences in the fossilized ''Sequoia affinis'' material to the modern redwoods of California. The foliage in the fossils is thinner and the female cones are smaller than the modern examples.<ref name="book"/>
There have been more than 130 species of pollen that have been identified in the shale beds at Florissant. These species represent samples from many different habitats that were located near and around the lake, as well as farther up the valley.<ref name="book"/>

Benthic diatoms are the dominant type of siliceous algae found in the beds. These are easy to fossilize due to their silica shells. During periods of volcanism, the influxes of silica from volcanic ash lead to blooms of algae, which lead to algal mats and the exceptional preservation of the fossils. Florissant is significant in that it is one of the earliest known examples of freshwater diatoms.<ref name = "Harding,2000" />