Willow Oak

Associated Smithsonian Expert: Jonathan G. Wingerath, M.F.S.

Jonathan Wingerath working with fossil plant specimens at the National Museum of Natural History

Photo by Smithsonian Institution

Jonathan Wingerath is a Museum Specialist who manages the Paleobotanical collections at the Smithsonian National Museum of Natural History. He grew up in northern New York State and became interested in paleontology as a Geology major at St. Lawrence University. During vacations he explored the fossil bearing outcrops of local Ordovician limestones, finding an occasional trilobite, brachiopod, or crinoid fragment. At Yale, he received his master’s degree in Forest Soils and Hydrology. Between the summers of 1988 and 1989 he was employed by the State of New York to map large sections of the surficial geology in the St. Lawrence Lowlands. He also worked as a Peace Corps volunteer in the Department of Concepcion, Paraguay, teaching agroforestry practices to farmers, public school teachers and their students. Wingerath began his career at the Smithsonian in the Division of Sedimentology, applying his knowledge of geology, soils, and hydrology to projects involving the Nile River, Nile delta, and offshore sedimentation in the Levant region. His current work involves organizing and housing approximately 6.5 million fossil plant specimens, facilitating the work of paleobotanists at the Smithsonian and scientists from all over the world. He also prepares thin-sections of paleontological, biological, and geological materials.

Meet our associated expert

This image was obtained from the Smithsonian Institution. The image or its contents may be protected by international copyright laws.

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Fossil flower from Green River Formation dated to the early Eocene
Photo by Smithsonian Institution, Department of Paleobiology

About Flowering Plants (Magnoliophyta): Paleobiology

Flowering plants (or angiosperms) are the dominant group of plants today, but newcomers compared to others. The earliest, clear evidence of angiosperms is from the Cretaceous (about 100 million years ago). Classifying the earliest angiosperm fossils is difficult because they tend to be leaves and pollen, rather than flowers that would permit conclusive identification. Competing theories explain angiosperm origins: that they lived in disturbed areas along stream corridors from which they invaded lowland habitats; that they began as understory plants in dark forests; that they originated in coastal areas and moved inland; or that they started as aquatic plants. Questions about angiosperm origins led Charles Darwin to describe their origins as an abominable mystery. After they appeared on the scene, angiosperms gradually and then rapidly replaced conifers and seed ferns in ecosystems. Advantages may have been faster reproductive cycles, their intimate relationship with insects for pollination, large photosynthetic leaves, and improved systems to transport water and nutrients. Which combination of characteristics allowed angiosperms to become so successful is a question of continuing debate for paleobotanists.

What might this fossil leaf tell you about climate?
Photo by Smithsonian Institution, Department of Paleobiology

About Plants (Kingdom Plantae): Prehistoric Climate Change

The great biogeographer Wladimir Peter Koppen once said that plants are crystalized visible climate. He had studied the distribution of modern plants, but there is no reason to believe that ancient plants were not equally sensitive to climate. Indicators of paleoclimate, such as rainfall and surface temperature, can be found in the chemistry of fossil plants and the rocks that surround them. The form of the fossils themselves can also reveal a great deal about climate. For example, plants have tiny openings on their leaves (stomata) through which they absorb CO2 and release oxygen. More stomata occur in low CO2 atmospheres, and fewer in high CO2 environments. Some woody plants have growth rings, showing the alternation of favorable and unfavorable conditions. Leaf shapes can also act as thermometers. Leaves with serrated edges (toothed margins) are more common in cooler climates, whereas smooth-edged leaves dominate in warmer climates. By studying modern forests, and applying the findings to extinct plant communities, past climate conditions can be inferred. Changes in fossil plant assemblages mirror changes in global climate over time.