Thiselton-Dyer classes the flora of Tibet on the whole as belonging to the Arctic-Alpine section of the great northern division, but containing a purely endemic element.
Thiselton-Dyer has pointed out, what is called "specific stability" is a familiar obstacle to the producer of novelties, but one which he frequently succeeds in breaking down by cultural and other methods.
Thiselton-Dyer, "The New Origin of Species," Nature (1910); H.
Thiselton-Dyer (ed.), Flora Capensis, vols.
Thiselton-Dyer); Boissier, Flora orientalis, &c. &c.
An interesting species of Cycas, C.Micholitzua, has recently been described by Sir William Thiselton-Dyer from Annam, where it was collected by one of Messrs Sanders & Son's collectors, in which the pinnae instead of being of the usual simple type are FIG.
Cases have been recorded (by Thiselton-Dyer in Encephalartos and by Wieland in Zamia) in which the short carpellary cone-scales exhibit a foliaceous form.