1-24 



LOWEII EOCKNE FT.OliAS OF SOUTH EASTKliN NOliTH AMErUCA. 



"lemis remains coninioii durinsj tlic Ti'rt.iary in 

 Europe ami is foiiiul in America as late as tlie 

 upper Miocene lake of Florissant, Colo. The 

 ancestor of the existing Jledera helix Limie 

 occure in the Phocene of central France, and the 

 moilern form itself is found in the Pleistocene of 

 England, France, and Italy. A species of 

 Polyscias occm-s in the Pleistocene of Java 

 associated with P'ithecanthrn])iis (-rectus. 



The family UmbelliferiX', which includes 170 

 g<>nera and more than 2,000 existing species, is 

 distinctly an extratropical family witii numer- 

 ous boreal forms, chiefly herbaceous and of 

 relati\'ely modern origin. It is very sparingly 

 and doubtfulh' represented in the fossil state. 

 The only Wilcox form that suggests such an 

 alTmity is the fruit described as CarpoUthus 

 pi-angosoides, which greatly resembles the 

 existing genus Prangos Lindley. 



The third family of the UmbeUales, the Corna- 

 cese, is relatively small. It comprises only 16 

 genera and about 100 existing species, mostly 

 of the Temperate Zone. The majority of the 

 fossil forms are confined to the two genera 

 Cornus and Nyssa, although the oriental genus 

 Camj)totheca is represented by fruits in the 

 Dutch Pliocene. Cornus includes about 40 ex- 

 isting species of herbs and small trees, mostly 

 confined to theNorthTemperate Zone in Eurasia 

 and Xorth America but represented in Mexico 

 and also by a single species in Peru. More than 

 50 fossil species have been described. There 

 are at least 12 forms in the Upper Cretaceous, 

 all confined to North America, ranging from 

 Greenland to Alabama. There are about a 

 dozen Eocene species in America, Europe, and 

 the Arctic region, one of which is sparingly 

 represented in the Wilcox flora. Oligocene 

 records are few, but more than 25 Miocene 

 species have been described. The genus was 

 parti('ularly abundant at this time throughout 

 central Europe and was also represented in botli 

 North America and Asia. About 5 Pliocene 

 species are recorded from Spain, France, Italy, 

 and Japan, and the genus has affonled Pleisto- 

 cene material in New Jersey, Holland, England, 

 and other covmtries. 



Tlie genus Nyssa Liime (including also Xys- 

 sidium Heer and Nyssites Geyler and Kink- 

 eliii) comprises about 7 existing species that 

 range from slirubs to large trees and luv natives 

 of southeastern North America and eastern and 

 central Asia. It is represented by more t lian .">() 



fossil forms, most of tlieni l)ased on the cliarac- 

 teristic costate stones. The ohh^st Icnown 

 forms come fi-om beds near the base of the 

 I p])er Cietaceous (Dakota and Tuscaloosa) of 

 North America. By F'ocene time Nyssa had 

 reachetl Alaska, Greenland, and Europe. 

 There are 2 characteristic species in the Wilcox, 

 both based on stones, and a third occurs in the 

 overlying dejxisits of the Claiborne group. In 

 the lignite de])osit of Brandon, Vt., wliich is of 

 uncertain but ])robably early Tertiary age, no 

 less than 18 so-ciiUed species of stones have 

 been described. Tiiough doubtless the specific 

 differentiation is overrefined, the abundanc of 

 Nyssa in New England at that time is indicated. 

 Nyssa is abundant in the Eiu-opean Oligocene, 

 and survives on that continent in the Pliocene. 

 There are Miocene species in New Jersej', 

 Virginia, Europe, and Asia. A Pliocene species 

 occurs in Alabama. Some of the mod(^rn 

 species are common in tlie Pleistocene of this 

 country from y^ew Jersej^ southward. 



Though much remains to be learned regard- 

 ing the liistory of the (\)rnace£e, it seems clear 

 that the two genera, Cornus and Nyssa, that 

 have yielded fossil forms are types that origi- 

 nated in Xorth America during the Cretaceous. 



No family of the Choripetalse has succeeded 

 in maintaining a world-wide distribution, as 

 have several families of IVIonocotyledona^ and 

 Gamopetalfe. No distinctly boreal group has 

 been developed, as among the Gamopetalas 

 (Ericales). Certain great families characterize 

 the X^orth Temperate region, and these are all 

 herbaceous forms, believed to be of relatively 

 recent origin, such as Poh'gonacess, Carj'ophyl- 

 lacese, Cruciferse, Saxifragacese, Onagracese, and 

 UmbeUiferse. Though atjuatic forms are com- 

 mon, this habit does not characterize whole 

 families, as among the ^lonocotyledonae. Tlie 

 Choripetahe ])redoininate in the American 

 Tropics, and many of tlie families in the Wilcox 

 flora probably originated in that region. 



The second grand divisit)U of the Dicotyle- 

 domr, the Ganiojietala' (Sympetala=>) , const itutes 

 a rather well defined group, presumably de- 

 rived from the Clioripetala% which is character- 

 ized by a complete cyclic arrangement of the 

 floral jiarts, a corolla that is generally gamo- 

 petalous, and ovules that have a small nueellus 

 and as a rule a, single integument. The Gamo- 

 petala? contain nine or ten orders and more than 

 50,000 existing species. Most of the orders 



