Introduction
Craigia W.W. Smith & W.E. Evans is one of the 3 living genera of trees which comprise subfamily Tilioideae of the angiosperm family Malvaceae. It is more closely related to Tilia (limes), than to the 3rd genus (Mortoniodendron).
As a living genus it is confined to southern China and adjacent northern Vietnam. where there are 1 or 2 living species (one species has not been seen since discovery and may be extinct. Descriptions of both species, Craigia yunnanensis W.W. Smith & W.E. Evans and Craigia kwangsiensis Hsue can be found in the recent Flora of China [1].
In earlier periods the genus had a much wider range. It was common in the Tertiary of western North America, Europe and Asia. Extinction in Europe may be part of the widespread depauperisation of the European flora as a result of the Pleistocene glaciations; extinction in North America appears to be have earlier. The sister group, Tilia, is still present in Europe (and Eastern North America) but shows its greatest diversity in temperate East Asia.
Craigia is also a genus of amoebas.
Description
Craigia are deciduous trees. The living species have long petiolate leaves with elliptic or oblong blades and denticulate margins.
Craigia yunnanensis W.W. Smith & W.E. Evans