COMI'OSITIOX OF THE FLOKA. 



was present in tlio omliaymcnt aixni in upjior 

 beds of tlie Ui)])cr Cretaceons (Ripliiy forma- 

 tion of Teimessoo). Its ni<iasi<u- r(i])niS(intation 

 in Wilcox time may Ix; diu^ to tlie more tro|)ical 

 climate. The modm-n Myricas are temperate 

 and subtropical, and a numltcr of the species 

 are coastal forms of eitluu- s\vam])s or sand 

 dmies. Jlyrica (lirdnoidrs- was «;vid(sntly a 

 coastal form and so was Afijriai irilcoxciini.s, a 

 species veiy similar to tiie existing; Mijiiai 

 ccrijav, wliicli ranges from \<*\v J(^rs(!y to 

 Texas, and is also found on tlie llerinudas and 

 Bahamas. Myrlca cvrifau is most. al)undant 

 and vigorous in tlie sandy swamps along the 

 South Atlantic and Gulf coasts, and its liabi- 

 tat may be compared witli that of Mijnca vnl- 

 coxeiisis, which seems to l)e the anc(!stral stock 

 of a very similar species that occurs along 

 the middle Eocene (('lail)orne) coast of the 

 embaj-ment. 



The order Fagales, which includes many 

 well-known timber trees of tlie Temperate Zone, 

 is comprised in the two families Betulaceie 

 and Fagacea^. These families together con- 

 tain about 450 existing species, about three- 

 fourths of which belong to the Fagacese. 

 Although the Betulacere arc; characteristically 

 developed in the Upper Cretaceous of North 

 America, they are unrepresented in the Wilcox 

 flora, probably because the climate was too 

 warm, and this probability may also account 

 for the absence of true oaks, the Fagacese 

 being represented in the Wilcox flora only by 

 the genus DryophyUum, which there includes 

 five rather widespread and locaU}' common 

 species. 



The genus DryophyUum is of world-wide 

 distribution and shows consistently uniform 

 characters tliroughout many horizons of the 

 late Cretaceous and early Eocene from the 

 Senonian to the Ypresian stage. It especially 

 characterizes the dawn of the Eocene and 

 represents the ancestral stock from which the 

 genera Castanea, Castanopsis, I'asania, and 

 Quercus took their origin, although this 

 origin was in the late Cretaceous. As might 

 be expected, DryophyUum has long since be- 

 come extinct. The Wilcox species were aji- 

 parently strand types, as were also tlie many 

 species enumerated by Debey, the describer of 

 the genus, from the sandy shores of the Upper 

 Cretaceous sea of Rhenish Prussia. l)ryo])liyL 

 lum is abundant in the IMontian of Belgium 

 50243°— IG G 



and in the littoral sands of Ostricourt and 

 IJelhni in France. In the systematic chapter 

 (letaUed comparisons are made between the 

 Wilcox and the foreign species which show a 

 striking parallelism. 



The Urticales include tlie families I'hnacea', 

 Moracea', and Ul•ticacea^ which togetiier con- 

 tain about l.fiOO (wisting species. The Irti- 

 caccni^ are largely herljaceous forms, and the 

 Ulmacea' are mostly extratropical. 



Th(^ Ulmacea) comprise 13 genera and about 

 1-10 existing species, widely distributed in 

 temperate and tro|)ical regions. A single 

 species of i'lancra, descnl)ed originally by 

 Newberry from the western Eocene, is (hnil)l- 

 fuUy identilied from the Wilcox. The genus 

 is monotypic in the existing flora and is con- 

 tiiu'd to wet swampy situations in the warm 

 temperate region of southeastern North Aniei- 

 ica. Its geologic history goes back to the 

 I'])per Cretaceous, species having been recog- 

 nized along the Atlantic coast from North 

 Carolina northward in beds of that age. Thus 

 there is no reason why it should not have been 

 present in the early Tertiary of the embayment 

 unless the climate was too warm. 



The MoraccEB, by far the largest family of 

 the order Urticales and the only one certainly 

 represented in the Wilcox flora, contains be- 

 tween 900 and 1,()()0 existing species segre- 

 gated among about 55 genera, of which the 

 genus Ficus is by far the largest, including 

 al)out 60 per cent of the existing species of 

 tlie family. The Moracere are distinctly trop- 

 ical and warm temperate types and are most 

 abundant in the oriental tropics, although the 

 dominant genus Ficus is widespread and the 

 family also is largely represented in the South 

 iVjiierican tropics. 



Then) are at least 18 monotypic genera, of 

 which 1 is North American, 4 South American, 

 4 African, and 1) Australasian. No single tribe 

 is confined to a single continental area and all 

 show apparent anomalies of distribution due 

 to our lack of knowledge of their geologic his- 

 tory. The genera Ficus, Artocarpus, and 

 i\j'tocar|)idium go back to the base of the 

 Upper Cretaceous and numerous other genera 

 appear in the Eocene. 



There are 2.3 species of MoraceiB in the Wil- 

 cox llora. The genus ^Vi'tocarpus is repre- 

 sented t)y :> weU-marked species. In the ex- 

 isting flora tiie two score known species of 



