Gress: Fossil Plants of the Dakota. 315 



MALVALES. 



Family STERCULIACE.^. 



Genus Sterculia. 



The leaves which I have referred to this genus show a close rela- 

 tionship to Platamis, particularly in the arrangement of the primary 

 and secondary veins and in the lobing. (See discussion of Platanus.) 

 Sterculia mucronata Lesquereux, as figured by Lesquereux in The 

 " Flora of the Dakota Group," PI. 30, figs. 1-4, and the several speci- 

 mens, which I have referred to that species, all very closely resemble in 

 outline, in branching of the primaries, and in lobing, the leaves of our 

 modern Platanus Wrightii Watson. The lobing is also very similar 

 to our modern Liquidamhar styracifliia, but the branching of the pri- 

 mary veins differs. 



44. Sterculia Snowii Lesquereux. 



Sterculia Snozvii Lesquereux, The Flora of the Dakota Group, U. S. Geological 



Survey, Monograph XVII, 1892, p. 1S3, PI. 30, fig. 5; PI. 31, figs. 2. 3, and 



PI. 32, and PI. 33, figs. 1-4. 



Knowlton, in Hill, American Journal of Science, L, 1895, p. 213. 



HoLLicK, The Cretaceous Flora of Southern N. Y. and New England, U. 



S. Geological Survey, Monograph L. 1906, p. 94, PI. 34, fig. 20. 

 Sterculia Drakei Cummins, Third Annual Report, Geological Survey Texas, 



1 89 1 (1892), p. 210, Text fig. 8. 



Description: "Leaves long petioled, membranous or subcoriaceous, 

 large, palmately two- to five-lobed; lobes entire, lanceolate, taper- 

 pointed or acuminate, greatly diverging; primary nerves palmately 

 three to five, from the top of the petiole, mostly simple, thick, per- 

 current ; secondaries thin, oblique, straight, or slightly curved in 

 traversing the blade, simply camptodrome. The largest leaves are 

 more than 20 cm. long from the top of the petiole to the apex of the 

 median lobe, and are quite as broad or broader between the apices of 

 the lateral lobes; the petiole generally preserved is more than 20 cm. 

 long, strong, inflated at the base. The divergence of the lobes aver- 

 ages 40°, the lateral ones being about at right angles to the median 

 nerve, and generally curved backward ; the primary nerves are thick, 

 the secondaries thin, often obsolete, close, parallel, at an angle of 

 divergence of 50°, curving quite near the borders, the curves forming 

 a kind of thin, marginal nerve along them; the areolation is obso- 

 lete." — Lesquereux, op. cit. 



