164 BERRY— LOWER EOCENE FLORA OF [April 25, 



Peryear. It is named from its resemblance to the genus Knightia 

 R. Brown, a genus of few existing species confined to the Australian 

 region but apparently represented in Europe during the Tertiary as 

 has already been indicated. 



The genus Banlcsia. with three Wilcox species, two of which are 

 particularly well marked and a probable fruit, Carpolithus protcoidcs, 

 is confined in the existing flora to the Australian region with about 

 50 species. The other genus of the tribe Banksieae is Dryandra R 

 Brown also with about 50 existing species confined to the Australian 

 region. It is much like Banksia in its foliar characters. Both genera 

 are found in abundance in the European Tertiary and undoubtedly 

 enjoyed a more or less cosmopolitan range during the early Tertiary. 

 Their ancestors probably entered the Australian region during the 

 Upper Cretaceous before that country had become entirely separated 

 from Asia, becoming adapted to the peculiar soils and climate of 

 Australia, while the stock in the northern hemisphere appears to have 

 been unable to stand the climatic changes and Tertiary competition 

 and thus became extinct. 



The Aristolochiales is placed by some students among the Gamo- 

 petalae. It includes besides the Aristolochiaceae, the two parasitic 

 families, the Rarrleisiaceae and Hydneracea?, altogether containing 

 about 235 existing species, of which 205 belong to the Aristolochia- 

 ceae, the only family of this order represented in the Wilcox flora. 

 The genus Aristolochia, to which a typical fruit from the Wilcox is 

 referred, is found in the American Upper Cretaceous and in both 

 Europe and America during the Tertiary. There are about 180 ex- 

 isting species all perennial herbs or climbing vines and widely dis- 

 tributed in both tropical and temperate regions, about ten species be- 

 ing found within the United States. 



The order Polygonales includes the single family Polygonaceae 

 with about 800 existing species segregated in about 30 genera, widely 

 distributed. They embrace herbs, shrubs, vines and trees, with 

 mostly cyclic flowers, and in their morphological features show some 

 evidences of transition between the previous choripetalous alliances 

 and the Chenopodiales. The geologic history of the family is prac- 

 tically unknown and it would seem that a large part of the specific 

 variation, particularly of the temperate herbaceous forms, was rela- 



