The environment of modern Florissant is dominated by a cold montane ecosystem with a coniferous forest of Ponderosa pines, limber pines, Rocky Mountain bristlecone pines, spruce, Douglas fir, and deciduous aspen trees. If you were to visit Florissant during the late Eocene, it would be a very different world of warm temperate and subtropical plants. The types of plants present would change as you moved away from the lake and up the drier mountain slopes (see upper left image). The marshy edges of the lake would have cattails and water lilies. Redwoods, false cedars, willows, poplars, apple trees, elms, hickories, maples, and extinct beech and elm relatives would dominate the wet valley bottom. As you transitioned into drier upslope areas, serviceberry, rose, currant, sumac, and pine would replace the valley bottom community. The hillside and ridge communities would include pine, oak, and mountain mahogany, while fir, pine, spruce, and hemlock would dominate the higher conifer forest communities.
While modern relatives of the fir, spruce, pines, serviceberry, rose, and currant can be found in the region today, other plants no longer have modern relatives in Colorado (see upper right image). In fact, you would have to travel to the west coast of the United States to find redwoods, more than 500 miles east to find hickories, and southeast Asia to find the hard rubber tree. Research indicates that the plants preserved are part of a non-analog forest community, which means that there is no modern equivalent to the Eocene forest found at Florissant Fossil Beds.