One feature all eudicots share is the shape of their pollen grains, which have three pores through which the plant's sperm cells are released. But there is no three-pored pollen in the clay where the fossil was found. That's puzzling, Jud says, since pollen has a hard shell that preserves it in the fossil record. Scientists use pollen as a marker of geologic time and environmental conditions, so a change in the evolutionary sequence of eudicots and their pollen could have important implications for many types of analyses.
"Either the plant was very rare, and we just missed its pollen," Jud says, "or it's possible that eudicot leaves evolved before (three-pored) pollen did."
Jud consulted paleobotanist Leo J. Hickey, who collected the leaf fossil at Dutch Gap in 1974. Hickey, a former director of Yale's Peabody Museum of Natural History, agreed the plant is an early eudicot. Hickey became a co-author of Jud's research paper, but he died of cancer in February 2013, before the paper could be published.
It was Hickey who told Jud the history of the Dutch Gap site, where Union generals trying to capture Richmond in 1864 thought the canal would be a strategic shortcut. Hickey knew the black laborers who dug the canal were forced to work against their will, though most modern histories don't say so.
Jud turned to Steven Miller, co-editor of the University of Maryland's Freedmen and Southern Society Project, where researchers analyze 2 million documents about former slaves' passage from bondage to freedom. Miller unearthed a protest letter from 45 impressed freedmen to the command of Union Gen. Benjamin Butler.
The men wrote that they were taken to Dutch Gap "at the point of the bayonet" and forced to dig for weeks without pay. When more laborers were needed "guards were then sent to take up every man that could be found indiscriminately
|Contact: Heather Dewar|
University of Maryland