ADDITIONS TO THE FLORA OF THE WILCOX GROUP. 



13 



curves close to the margin to join a campto- 

 drome tertiary from the outside of the main 

 pair of secondaries from the midrib. The ter- 

 tiaries, with the exception of the camptodrome 

 ones already alluded to, are thin and largely 

 immersed, exceedingly regular in their spacing, 

 and prevailingly percurrent, although they oc- 

 casionally fork and inosculate, as shown in the, 

 figured specimen. The. ultimate areolation is 

 fairly distinct in spots and must have been 

 entirely so in life; it shows relatively large and 

 prevailing subrectangular meshes. 



This fine species is obviously new and forms 

 a striking addition to the Wilcox flora, as its 

 modern relatives are all climbing or twining 

 herbs or shrubs prevailingly of wooded or 

 stream-side habitats. It is similar in form to 

 the Wilcox species Cercis wilcoxiana Berry but 

 entirely different in its venation characters and 

 obviously not related to that form. The pre- 

 viously known Wilcox species of Mt nispermites, 

 M. vrilcoxensis Berry, is a much more typically 

 ovate form with a prolonged acuminate tip and 

 but three instead of seven primaries. The 

 tertiary venation and the camptodrome arches 

 close to the margins are the same in both, and 

 neither shows the tendency toward a lobation 

 of the lamina, which is so pronounced a feature 

 in so many of the existing species of this 

 family. 



The existing species are too imperfectly 

 known and polymorphous to render detailed 

 comparisons with this Eocene form of much 

 value. The fossil is not unlike the leaves of 

 our common Menispermum canadense Linne, 

 which are nonlobate. It shows a similar 

 resemblance to the leaves of our common 

 Cebatha Carolina (Linne) Britton, which are 

 nonlobate, and similar statements might be 

 made with regard to a large number of exist- 

 ing species of the family. Among fossil forms 

 the most similar is Cocculus (Cebatha) latifolius, 

 from the Pliocene of France, described by 

 Saporta and Marion, 17 but this similarity is 

 of the same order as the comparisons with 

 recent forms just mentioned. 



The polymorphism of the existing species 

 renders it desirable to refer this new form to the 

 genus Me nispermites, implying a fossil form of 

 Menispennaceae of undeterminable generic 

 affinity. It might very well be ancestral to the 



17 Saporta, G. de, and Marion, A. F., Recherches sur les vegetaux 

 fossiles de Heximietix, p. 264, pi. 31, rigs. 4-7; pi. 32, fig. 1, 1876. 



genus Cocculus De Candolle, or Cebatha Forskal, 

 as modern taxonomists prefer to call it, as 

 Forskal's name was published in 1775, or 43 

 years earlier than De Candolle's proposal. 



The existing species of Menispennaceae 

 number about 350 in about 60 genera. All are 

 twining or climbing woody or herbaceous 

 plants with alternate exstipulate leaves and 

 drupaceous fruits. A majority of the species 

 are confined to moist tropical regions, but a 

 considerable number are found in both tem- 

 perate zones. None of the subfamilies are 

 confined to a single continental region, and 

 several of the genera are found on all the con- 

 tinents. 



The existing species of Menispermum, but 

 two or three in number, are confined to Atlan- 

 tic North America and eastern Asia, which 

 indicates a wider range during geologic time. 

 The genus Cebatha (Cocculus) is a large one for 

 this family, with about 30 species, its distribu- 

 tion including all the continents except Europe 

 and extending to the Hawaiian Islands. Sev- 

 eral fossil species that have been referred 

 directly to it or to the form genus Cocculites go 

 back as far as the Upper Cretaceous. A well- 

 marked species is present in the later Tertiary 

 of the Mississippi embayment, and it would 

 perhaps not be far from the truth if the present 

 species were referred to this genus. 



The family has 10 genera with about 75 

 species confined to the Western Hemisphere, 

 mostly in tropical South America. Asia has 

 13 peculiar genera; Africa, including Madagas- 

 car, has 14; and Australia has 7, all monotypic 

 and largely found in the peculiar environment 

 of Western Australia. The largest number of 

 existing species occur in tropical Asia, from 

 which about 150 are known, or about 50 more 

 than are known from America, which ranks 

 second in the number of existing forms. 



The fossils of the narrow triveined form of 

 some species of Cocculus (Cebatha) are rather 

 difficult to determine, for they show more or 

 less resemblance to some leaves in the families 

 Smilacaceae, Lauraceae, Urticaceae, Pipera- 

 ceae, Melastomataceae, and others. 



The wider leaves are more characteristic, 

 and species of Menispermum are recorded 

 from beds as early as the Oligocene of France. 

 The form genus Menispermites has numerous 

 Upper Cretaceous species, particularly of Ceno- 

 manian and Turonian age, and is recorded 



