• 9.4.] SOUTHEASTERN NORTH AMERICA. 217 



the genus Sassafridium confined to the American tropics. All of the 

 other genera are found on more than one continent. 



The tribes Apollonieae, Cryptocaryese and Cassythese are found 

 on all the continents but Europe. The Laure?e are Eurasiatic and 

 the Acrodiclidiese are confined to Central and South America, except 

 the genus Endiandra which with 16 species occurs in the East Indies 

 and Australia. 



The problem of correctly identifying leaves of the various genera 

 of this family is beset with almost unsurmountable difficulties, not the 

 least of which is due to the wide differences in usage among students 

 of the recent forms where the whole plant is available for study. 

 Long-continued paleobotanical practice has been to refer most fossil 

 leaves that lacked the more apparent characters of Cinnamomum or 

 Sassafras, Persea or Malapoenna, etc., to the comprehensive genus 

 Launis given at a time when Laitnts was used in a comprehensive 

 sense, and sometimes still more generalized by paleobotanists as 

 Laurophylhtni for lauraceous leaves of uncertain generic affinity and 

 not necessarily close to the existing species of Laitnts, in fact they 

 are in general not true species of Laitnts. I have departed from this 

 practise of describing new species of Laitnts for a variety of reasons 

 foremost among which is the very great affinities between the Wilcox 

 flora and the existing flora of the American tropics, the evidence 

 from the foliage of a large number of genera being coroborated by 

 fruits or seeds or wood anatomy. I have used this similarity with 

 a great deal, perhaps too much, confidence and the result has been 

 that the following stand out as the more important lauraceous types 

 iii the Wilcox flora : 



Nearly all are seemingly members of the subfamily Persoideae 

 and under this subfamily of the tribe Cinnamomere as segregated in 

 Engler and Prantl's " Xaturlichen Pflanzenfamilien." 



Eirst the genus Ciiinamomitiii, usually readily recognized and 

 certainly represented in our Eocene floras. 



Second the genus Persea, represented by the larger and wider 

 forms with the typical venation of this genus. 



Third the genus Nectandra, so abundant and characteristic of 

 the existing flora of tropical and subtropical America, represented by 

 several species very close to modern forms. 



