E. V. Wulfif 



—84- 



Historical Plant Geography 



Taxodium, represented now by three species, T. distichum, T. im- 

 hricarium, and T. mexicanum, distributed along the south Atlantic coast 

 of North America and in Mexico. In a fossil state it is known through- 

 out almost all of North America and also in a considerable part of 

 Europe and Asia. 



Glyptostrohus, a. genus very close to Taxodium and represented now 

 by but two species, G. pendulus and G. heterophyllus, found in eastern 

 Asia (China). In contrast to the two preceding genera that died out in 

 Asia, Glyptostrohus died out in America. In a fossil state (from the 

 Cretaceous) it is known in Greenland — G. groenlandicus and G. inler- 

 medius. From Tertiary deposits two species are known: G. europaeus 

 — from southern Europe to the arctic zone and in North America; 



Fig. II. — North Atlantic and Iberian ranges of : 40, Eriocaiilnn seplangiilare; 41, 

 Erica Mackaii; 42, Rubia peregrina; 43, Arbutus unedo; 44, Saxifraga geum; 45, 

 the genus Corema, C. alba (European), C. Conradii (American). (After Fernald). 



G. Ungeri — Switzerland, Spitzbergen, Siberia, North America, and 

 Greenland. 



5. North America-South America Type. — This type is characterized 

 by identical or closely related species found both in North and South 

 America but not having a continuous area. Here belong also those 

 species and genera that are represented in one of the Americas by 

 living forms and in the other by extinct forms. As an example of the 

 latter we may take the genus Sequoia, growing now in California but 

 in a fossil state found also in Chile. Among plants now growing in 

 both North and South America but not having continuous areas we 

 may take as an example the Sarraceniaceae, which family includes the 

 closely related genera Sarracenia, Darlingtonia, and Heliamphora. The 

 genus Sarracenia has six species distributed in the Atlantic section of 

 North America; Darlingtonia one species, D. calif arnica, in California 

 (Sierra Nevada Mts.); and Heliamphora one species, H. nutans, in 

 British Guiana. 



6. Europe-Asia Type. — This type of area is characterized by 

 identical or related species found both in Europe and Asia but not 



