The enduring mystery of Critchfield's spruce
This article originally appeared on Undark. The first and only time Steve Jackson spoke to Bill Critchfield was in the late 1980s. Critchfield, an authority on the conifers of North America, was at home recovering from a heart attack. Jackson, then a postdoctoral researcher at Brown University, had called looking for advice on how to tell jack pine from Virginia pine. Jackson was also curious about something the elder botanist had mentioned in a recent paper: mysterious spruce fossils from the American Southeast. The fossils dated to the end of the Pleistocene ice age, about 18,000 years ago...
Source: salon.com