286 



LOWER EOCKXE FLORAS OF SOUTHEASTERN NORTH AMERICA. 



from the top of tho jx'tiolo, (livcrging at acute 

 angles, the midrib and a laterjil on either sitle 

 of the same caliber, out^n* laterals thinner and 

 more or less obsolete. The latcrixl primaries 

 cm-ve outward and then upward in a rather full 

 eiiiTe and are camptodrome. Secondaries 

 om-ved and camptodrom<" ; two or three subop- 

 posite pairs arise from the upper part of the 

 midrib, and numerous outwardly du'ected, 

 camptodrome secondaries arise from the lat^'ral 

 primaries, and from these latter sc^oondaries 

 tertiary branches run to the maiginal teeth. 



These leaves, which are thus far confined to 

 the three localities enmnerated below, where 

 they are not common, suggest a relationship 

 with many genera, such as Cissus, Ficus, Grewia, 

 Ziz^']5hus, and Popidus. At first sight theu- 

 obvious affinities are with the numerous forms 

 from Greenland, Eui'ope, and western North 

 America that are commoidy referred to the 

 genus Popidus, as Populus arctica Heer, PopUr- 

 lus zaddachi Heer, Populus cuneata Newberry (a 

 variable and common form of the Fort Union 

 Eocene), Populus genetrix Newberiy, Populus 

 paleoinelas Saporta, or Populus glandullfora 

 Heer. I have discussed them with Dr. F. H. 

 Knowlton, who is inclmed to identify them 

 with Populus dapJinogenoides. Though this is 

 hardly the place for an extended discussion of 

 these forms of Populus, in a large measure 

 kno^\^l only from the pubhcations of other stu- 

 dents, it is singular that the Arctic and early 

 .■\jneriGan forms are palmately and not pui- 

 nately vemed, hke the modern species, and pre- 

 sent in a varyhig- degree other distinctive fea- 

 tures. The specimens under discussion, which 

 have relatively short and stout petioles and pal- 

 mate venation, are beUeved to represent the 

 modern genus Grewia Lume of the TiliaceiE, 

 wliich comprises between 75 and 100 species 

 that range from China and Japan aci'oss Malay- 

 sia to Queensland m Australia and westwai'd in 

 southern Asia to Arabia, and also extend to 

 tropical and southern Africa. Although it is an 

 Old World type in the modern flora, four or five 

 f((ssil species of Grewia have been described 

 from the early Eocene of the Rocky Mmmtain 

 region and from the Arctic regions, as well as 

 from the Eocene, Oligoc.cne, and Miocene of 

 Europe. Eight or ten fossil species are known, 

 and in the allied genus Grewiopsis the fossil spe- 

 cies, which number more tiian a score, are espe- 

 cially characteristic of the early Eocene, ])oth 



in this country and abioad. Th" present spe- 

 cies is distinct from all tlie previously described 

 species, jdthough it resembles some of the foims 

 that have b;'en refeiTed to the widespread 

 (rrewia crenata Heer.' Its similarity to some of 

 the forms desci ibed by Lesqucreux - from Car- 

 bon, Wyo., as Z'lzijphus meelci may also be 

 l)ointed out. Lesquereux compared those forms 

 with Grewia crenata., and though what appears 

 to be the nonnal form of this variable species is 

 not especially suggestive of the plant from Ten- 

 nessee, some of the variants, such as the speci- 

 men shown in LesquereiLx's figure 11, are de- 

 cidedly smiUar but. have thiimer and more aero- 

 drome laterals and lack the distal secondaries. 



Grewiopsis tennesseensis resembles the Tusca- 

 loosa (Cretaceous) species Grewiopsis tuscaloo- 

 sensis Berry and may be genc^tically related to 

 it. 



Occurrence. — Wilcox group, between 3 and 4 

 miles below Hamilton, on Sabine River, Sabme 

 County, Tex. (collected by A. C. Veatch). Old 

 Port Caddo Landing, Little Cypress Bayou, 

 Harrison County, Tex. (collected by T. W. 

 Vaughan). Lagrange formation (in beds of 

 WUcox age), 1 mile south of Grand Junction, 

 in Favette County, Tenn. (collected by E. W. 

 Beiry). 



Collections. — U. S. National Museum; New 

 York Botanical Garden. 



Faonily STEKCTJLIACEa;. 

 Genus STERCULIA Linne. 



Sterculia pcryeakexsis Berry, n. sp. 



Plates LXXII, figures 2 and 3, LXXIII, figure 1, and 

 LXXIV, figure 4. 



Description. — Leaves medium sized to large, 

 for this genus, palmately 3 to 5 lobed from a 

 point at or below the middle. Maximum 

 length IS centimeter's. Maximum width, from 

 tip to tip of the upper lateral lubes, 16 centi- 

 meters. Margins entire. Texture subcoria- 

 ceous. Lol)es vary from narrow, lanceolate, 

 and conically pointed to broad and ovate, the 

 tenninal lobe slightly larger than the princi])al 

 lateral lobes. The maximum length of the 

 lobes is 10 centimeters and the maximum 

 width, at the base, ranges from 3.5 to 6 centi- 

 meters. The upper lateral lobes each form an 

 angle of about 40° with tlie terminal lube, from 



1 Ileer, Oswald, Flora ten iaria Helvetife, vol. 3, p. 42, pi. 109, figs. 12-21; 

 pi. 110, flKS. 1-11, 1M9. 

 ■ Le.'quereux, Leo, The ■lcrti:iry flora, p. 27.'), pi. .51, figs. U>-H, 1S78. 



