72 THE FLORA OF THE DAKOTA GROUP. 



Tliere is only one leaflet, 5"'" to G""' long, 2"" Ijroad l)et\veen the parallel 

 borders, with thirteen pairs of secondaries joining tlie niidril) at a ))road 

 angle ot" divergence of 00°, then running upward and following the borders 

 in sini})le festoons, parallel and equidistant. 



Habitat: Kansas. 



Order PLATANACE^. 



Platanus prim^va Lesq. 

 PI. VIII, Figs. 7-8b ; PI. X, Fig. 1. 



Cret. FI., p. 69, PI. vii, Fig. 2; PI. xxvi, Fig. 2. 



Leaves large, palmately trilobate, broadly rhoniboidal in outline, 

 deeply, distantly dentate ; lateral lobes simple, short; nervation platauoidal, 

 tripalmate ; lateral primaries suprabasilar. 



This species is now represented by a large number of specimens. 

 Among others a very large one is covered with fragments of ftiur leaves, 

 one of which is represented on PI. X, Fig. 1, and another, on PI. VIII, Figs. 

 8-8b, smaller, but net^rly entirely preserved with its petiole and a raceme 

 of flowers, which I consider as referable to this species. In all the leaves 

 examined, one of Avhich, the largest, is IT"™ long and more than 20"° between 

 the extremities of the lobes, the lobes are more or less distinct, in none, how- 

 ever, less than in PI. VIII, Fig. 7-, and always distinctly, distantly dentate. 

 In this last s])ecimen the lobes and the teeth appear blunt; but the border 

 of the leaf is somewhat eroded on account of the softness of the sandstone and 

 probably the teeth are rendered obtuse by obliteration. The base of the 

 leaves is also g-enerally more prolonged dowmvard, descending ftir below 

 the primary lateral nerves, or lower than observed fc^rmerlv in the speci- 

 mens figured in my Cretaceous Flora. But this character is of no impor- 

 tance, as the same difterences are coimnonly remarked on the leaves of the 

 living P. oii'idi'utnUs L.', to which the fossil ones are remarkably similar in 

 form and size. Indeed, (•omj)aring the leaves of P. primceva of the Dakota 

 Group with those of P. HaijdenU of the Laramie, those of P. GuUhhiuc of 

 the Miocene, those of P. apju'iidiriikita of the auriferous gravel dept)sits of 

 the old Pliocene of California, and those of the living P. ocridentalis, one 

 sees the original type so clearly and distinctly preserved that, overlooking 

 the gi-eat difterences of age, it would be difficult to separate these leaves 

 into diftereut species. 



