CdMI'dSmoX OF Till". FLOHA. 



To 



C()sm()])<)litnn typ(^, luul slout coi-iaccdiis fronds 

 and ni.-iy liavc; IwH'n transjioi-tcd, sinc(> it occurs 

 at only two localities in tlio Wilcox, and at onc^ 

 of those it is in a fragmcMttary condilion. This 

 supposition receives some support from its 

 presence in llu^ l)asal Iviceiie of tlui lioci<v 

 Mountain ])rovince afler liK^s('.a liad withdrawn 

 fr<Mii tliat area and aft(M- there had been a hifj^e 

 amount of volcanic nclivilv and more oi- less 

 uplift. The genus Meniphylloides is a uni([U(^ 

 type, as yet peculiar to tlie Wilcox flora, al- 

 though it is closely related to tlie simihirlv 

 unirpie gemis Menipliyllum Ettingsliausen and 

 Gardner, from th(( middle Eoceiui (Lutetian) of 

 England, and holli are closely related (o and 

 possibly the ])rogenitors of tlu> existing genus 

 Meniscium, which has at least one sjK^cies that 

 is close to the Wilcox form. MeiiipliyHoi<h's 

 is found at only thre(> localities near the top of 

 the Wilcox and its probable habitat is not 

 known. The remains are brok(Mi l)u(: are asso- 

 ciated with a typical strand (iora. 



It will 1)0 seen that of the Wilcox ferns wlios(^ 

 habitats can Ix^ surmised all are coastal types, 

 and when wo rcM'all that the maiidand was rela- 

 tively low tliroughout Wilcox time it is not 

 surprising that tln^ fcu'us are scarce. By a 

 specialization of haliitat in modern of[uatorial 

 regions a large part of the flora bocouKW ("lu- 

 phytic, the smaUer ferns lioing commonly so. 

 None of the mendx^rs of the! extensive Wilcox 

 flora can be rc^gariled as epiphytes with the pos- 

 sible exception oi Lycopodites? eoligniticus, W'hich 

 is such a rare and poorly represented form that 

 it is without signilicance. Apparently epi- 

 phytes w^ere not conspicuous in the Wilcox 

 coastal floras, so that this possi!)lo source of 

 additional fern species is also eliminated. 



The Gymiiospermffi, so conspicuous in Meso- 

 zoic floras, are relatively imimportant, lioth in 

 species and individuals, in the Wilcox flora, a 

 feature due to tlunr general relative unimpor- 

 tance in Cenozoic floras and to tlioir intoh'r- 

 ance of the habitats and climatic conditions 

 indicated by the Wilcox flora as a whole. Four 

 Wilcox gymnosperms are referred to the rela- 

 tively moihn'ii family Pinacese and none of the 

 genera are especially close to Mosozoic types. 



These PinaccaB include the following: Some- 

 what poorly defined petrified wood which does 

 not merit especial comment, representing the 

 genus Cupressinoxylon of Goppert. The genus 

 Glyptostrobus, which contains but two surviv- 



ing species in tlie river bottoms of eastern Asia, 

 is represented by foliage and seeds i-eferred to 

 Gh/ptostroh'us eumjiwus (Brongniart) lloor. 

 Tliis species is exceedingly conuiion at a large 

 number of localities and liorizons in the nortli- 

 ern liemispliere tliroughout the Tert iary period. 

 In North America it is rei)resent(Ml from the 

 basal Eocene to the Pliocene, and thougii it 

 jirobably includes more than one botanic s])e- 

 cies no basis htr its segregation except by geo- 

 graphic or geologic divisions is discernible. 

 The genus Ta.xodium is s])aringly i'epresente(I 

 by foliage and seeds. Tlu> hmves are referred 

 to Ta.Todiiiiii ihihhnii (Sternberg) Ileor, a spe- 

 cies whose distribution and g(M)logic range are 

 as wide as that of (i/i/jiUixtrohii.^ curojixus. It is 

 found in North America from the base of the 

 Eocene to the Miocene Chesapeake group and 

 In the Pliocene of the Gulf coast if ])asses iii- 

 s(Misibly info the Pleistoceni' and still existing 

 bald cypress. Arthrotaxis, still living in the 

 meso])hytic areas of Tasmania, is represented 

 l>y cone scales. No traces of the genera Se- 

 quoia or Podocarpus have been discovered. 



Though gymnosperms are so poorly repre- 

 sented in the lown-r Eocene of the embiij'nient 

 area they arc not without significance.' The 

 fact that they are so uncommon there, whereas 

 in more northern Eocene floras they are so 

 abundant, seems to show that the Wilcox cli- 

 mate was unfavorable. The only possible 

 adverse condition which the flora of the; Wilcox 

 as a w'hole indicates is too warm a temperature, 

 which, if correctly inter])retod, indicates at 

 least some development of climatic zones in 

 the lower Eocene. The habitats of Glypto- 

 strobus and Taxodium in the lower Eocene 

 were apparently the same as those of the exist- 

 uig species, and they thus confirm the predi- 

 cated character of the physical conditions in 

 Wilcox tim(>. Both genera are only known 

 from the HoUy Springs sand or middle Wilcox, 

 which was deposited at a tim(> w^hen the coastal 

 n'gion stood at about sea lev(>l and was trav- 

 ersed by sluggish nioandei-ing streams. The 

 Glyptostrobus twigs are found in the (>sluary 

 of a middle Wilco.x river, associated wilii unios 

 and thickets of Sabalites. The Taxodium 



' The petrified woods from the Wilcox were not sectioned in time to 

 be described in Uiis report. \ mimberare coniferous, and Ihut conifers 

 wore more abundant during Wilcox time than their foliafie remains 

 have indicated is alsoshown by the canneloid lij,'nite from I.cster, Ark., 

 described by While (Rur. Mines Bull. 3s, p. 19, l<ji;i). which is largely 

 made up of resin concentrated by ihe decay of couilerous woods. I'ollen 

 ex iiies of conifers are also reported from the Wilcox lignites at Lester 

 by Thiessen ridem, p. 234). 



