40 The Plant World. 



the preglacial flora of Europe was equally close to that of North 

 America as it was to eastern Asia.with European cypress swamps, 

 with magnolias, tulip trees, sassafras, ginkgoes, torreyas, etc. 

 Then came the Continental ice sheets with the result that from 

 the westernmost point of Spain eastward to the heart of Asia 

 we find that there was an almost continuous barrier cutting off 

 the southward retreat of the flora— the Pyrenees, Alps, Carpa- 

 thians, Balkans, Caucasus, Altai, and Himalayas, with their 

 locally extended glaciers, with the Mediterranean sea and its 

 Asiastic eastern extensions, and a few arid tracts to complete 

 the chain. In eastern Asia and along the west and east coasts 

 of North America, especially the latter, the mountains, for the 

 most part less elevated than the Eurasiatic chains, trend more 

 or less north and south instead of east and west, consequently 

 a large element was saved to the comparatively impoverished 

 post-glacial flora which would otherwise have suff"ered great losses 

 as it did in the European and western Asiatic region. 



The beautiful Bald Cypress {Taxodimn distichtim) proves 

 no exception to the foregoing statements, in fact the members 

 of the sub-family of conifers to which it belongs (Taxodieae) are 

 all remarkable for their present isolation, peculiar distribution 

 and ancient lineage. Four of the genera with only five species 

 in all the existing flora are endemic in the China-Japan region, 

 Sequoia occupies its last footing on our Pacific coast, Arthroiaxus 

 is Australian and Taxodium is eastern North American with a 

 climatically stranded form in Mexico. 



When we turn to the geological record we note that no fossil 

 species of Cypress have been recorded with certainty from strata 

 ,as old as the Cretaceous, although it is quite possible that some 

 of the twigs of conifers which are usually referred to Sequoia may 

 really be those of the Cypress, the fact that some of them were 

 deciduous might also suggest this. In the earliest Eocene, how- 

 ever, in the days when the primitive mammalian fauna was re- 

 placing the last of the dinosaurs, we find the ancestors of the 

 Cypress with an almost cosmopolitan range. These records are 

 very numerous and are based upon the remains of leafy twigs 

 which seem to. have thus early acquired the deciduous character 

 for which their modern descendant is remarkable. Cone scales 

 are also found and sometimes the wood showing the character- 

 istic anatomical features of the genus is preserved. Such an in- 



