CDMI'OSriION OK TIIK KI.OHA. 



113 



wliich contains 2 species <lescrihiMl l>y Viguier 

 from casts of wonderfully ])reserve(l flowers 

 as well as fruits from the celehratetl trav<'rtines 

 of Sezanne, aJid referred with great certainty 

 to the Lasiopetiilea'. 



The tribe Dombeyea\ which inc ludcs 7 genera 

 and about 75 existing sp(>cies, is almost entii-ely 

 coiifined tOxVfrica and the adjacenl islands, oidy 

 5 or G species of the genus Melluinia Foi-skal 

 ranging from Arabia to Farther India. This 

 tribe is represented in fossil floras by the genus 

 Dombeyopsis Unger, named from its supposed 

 affinity with the modern genus Dombeya 

 CavaniUes, wliich embraces 40 African s])ecies, 

 mostlj' from Madagascar. About .U) species 

 have been referred to Dombeyopsis. They 

 are liable to be confused with Luhea, Grewia, 

 and other forms of the allied family Tiliacea^. 

 There are 3 species in the Laramie Cretaceous, 

 2 in the Denver formation, 12 (according to 

 Massalongo) in the upper Eocene of Monte 

 Bolca in Italy, 5 in the European Oligocene, 

 and 6 in the Miocene of Iceland, France, 

 Switzerland, Prussia, Silesia, and StyTia. A 

 Pliocene species is recorded from central 

 France. Fossil wood described as Dombey- 

 oxylon is recorded by Sch(>nk from the late 

 Tertiary near Cairo, Egypt. 



The Buettneriea? are represented by a doubt- 

 ful species described from the Miocene of Colo- 

 rado and probably by some of the fossil forms 

 referred to other genera, for instance some 

 of the palnuitely veined Ficus-hke forms, 

 such as Ficus occidentalis and Ficus scTivm'peri, 

 both of wliich are present in the Wilcox flora. 

 Flowers of Buettnei'ia wer(> reported from 

 Sezanne by Solms-Laubach, but should ])rol)a- 

 bly be referred to the subse<juently described 

 genus Sezannella, jn-eviously mentioned. 



The Helicterese are represented by a doubtful 

 species of Helicteres i>inne described from the 

 Pliocene of Italy and by forms refeiTed to the 

 existing genus Pterospermmn Sclu-ebei' or to 

 the extinct genus Pterospermites I leer. More 

 than HO species have been d(>scribed. There 

 are 9 or 10 in the Upper Cretaceous, all of 

 which are Xortli American, and their cond)iued 

 range extends from A'ew York to western 

 Alabama, throughout the Ko(-ky Mountain and 

 Great Plains province and in the Atane beds 

 of Greenland. There, an- about a dozen 

 Eocene species, all North American, except a 

 single species in the Palcocen(> of I'ranccv 'Yho 



50243°— 16 8 



American forms extend northward to west 

 Greeidand and Alaska. There are 2 or o 

 species in the European Oligocene and 10 

 Pliocene species tlu-oughout Europe and in 

 western North Amei-ica (Yellowstoue Park, 

 California, and tiie mouth of Mackenzie Kiver). 

 A single I'liocene s])ecies is recorded from 

 France. This ty]ie ])robably origiiuited in the 

 Western IIemis])here, since it is so abundantly 

 re])resent('d in that region durhig the Upper 

 Cretaceous and Eocene. The modern species 

 of Pterospernmm are, however, confined to 

 eastern troi)ical Asia. 



The order Parietales includes 30 families and 

 more than 1,000 existing species. The largest 

 famihes are the Guttifera; (775 species), Fla- 

 courtiacea; (530 species), Begoniaces (425 

 species), Violacea> (400 species), and Diptero- 

 carpaceije (330 species). None of these families 

 are found in the Wilcox flora, where the order is 

 represented l)y the 2 families DiUeniacese and 

 Ternstrcemacese. The Parietales are prevail- 

 ingly syncarpons and show afhnities with the 

 Ranalian plexus through the DiUeniaeea', 

 which were formerly referred to that order. 

 The alliance as a whole is complex and includes 

 several divergent lines of development with a 

 sradual increase on the whole in floral com- 



o 



plexity. 



The family DLUeniaceije contams 14 genera 

 and about 275 existing species found on all the 

 continents, the genus Tetracera being cos- 

 mopolitan in the Tropics. The genera Empe- 

 doclea, CurateUa, Doliocarpus, and Davilla, 

 which include 50 species, are confined to the 

 American Tropics; llibertia and Pachynema, 

 which include 75 species, are Austrahan; 5 

 genera and 25 species are confined to the 

 Asiatic Tropics; the genus Saurauia (or Sau- 

 rauja), which comprises about 60 species, is 

 conmion to Asia and South America; and the 

 genus Dillenia, which contains about 25 species, 

 ranges from Asia to Australia ; so that on the 

 whole tlie family is ]irevailingly oriental in the 

 existing flora. 



The fossil record is unfortunately most m- 

 complete, though it illustrates the wider range 

 of the genera in response to mUder chmatic con- 

 ditions in both the North Temperate and South 

 Temp(>rate zones during the Tertiary, and also 

 the fact that several of the modern American 

 genera have been American through their 

 known geologic history. Thus Erapedoclea, 



