A Fossil Buttercup

Abstract

WHEN we examine a catalogue of fossil plants, such as that for North America recently published by Knowlton, we are struck by the enormous number of recorded species, and readily receive the impression that the flora of former ages is quite well known. It is only when we make a more critical investigation that we perceive the great gap in our present knowledge. We do, perhaps, know a fair proportion of the trees and deciduous-leafed shrubs of a number of geological periods, but when we look for the herbaceous flora the limitations of our knowledge at once appear. Thus the Ranunculaceæ, an extensive family in the present North American flora, do not furnish a single definitely recorded fossil in the same area. Dawson in 1875 vaguely referred to a Thalictrum, without specific name, supposedly from the Eocene, but it is not to be taken seriously. Schenk thought the fossil genus Dewalquea presented a certain analogy with Helleborus, but it is now referred to quite another family. It is, of course, impossible to suppose that the Ranunculaceæ were absent from North America during Tertiary times; they simply must have escaped preservation or observation. To those who would see in the geological record a proof that herbaceous plants did not exist in the past, or were extremely rare, we can only reply that the record as it stands proves too much. To accept it at its face-value postulates the impossible. The general proposition that the herbaceous flora is, on the whole, more recent than the woody may be valid, and has much to recommend it.