Flowering Plants

Like an ivy, I was a vine that climbed trees and blocked out sunlight to the forest floor. I produced beautiful flowers that opened to the sunlight at the top of the forest canopy.

Unsplash Photo / Bogdan Locovei

Angiosperm plants first evolved and began to flourish during the Cretaceous Period. Angiosperms are flowering plants that produce seeds within an enclosure such as a fruit. Diverse angiosperm shrubs and smalldiameter trees thrived in the open-canopy Cretaceous Denali forests of gymnosperm trees. Menispermites is a fossil form name referring to leaves that look similar to those of the modern Menispermum (which means "moonseed"). Platanoid shrubs are related to modern members of the Platanaceae or "plane-tree" family.

Identification Level: Order and Genus

Alder is the common name for the genus Alnus. Some leaf fossils superficially resemble alder leaves, but they lack more evolved features that would assuredly link them to the modern alder. Menispermites leaves were preserved well enough to identify them to the fossil leaf form genus. Platanoid leaf forms were highly diversified during the Cretaceous. They exhibit affinities to two different plant lineages, the Hamamelidales and the Proteales.

 

Photo by Colby Wright

Where do I live?

Alder-like shrubs lined the edges of streams, creeks, and lakes. The Menispermites vine thrived in the open canopy forest, weaving its way through the trees above the wet floodplain. Platanoid shrubs lived in the understory of those same gymnosperm forests and lined the channel banks.

How do we know I lived in Denali?

Menispermites leaf fossils have been found near Sable Mountain in Denali, typically in association with conifer tree remains. Alder-like shrub leaves have also been found near Sable Mountain. A variety of platanoid leaf forms have been found all over Denali.

 

How do I size up? - These flowering plants had a wide variety of leaf sizes, from smaller than a postage stamp to larger than a dinner plate. One shrub was most likely capable of producing varying sizes of leaves within a given part of the plant.

Fun Fact

Leaf fossils can be used to estimate what the ancient climate was like. There is an observed correlation between temperature and precipitation, and modern leaf characters such as toothed margins. This correlation can be applied to fossil leaves.