DESCmrTION OF SPECIES— SAPINDACEiE. 263 



are small, the largest seen measuring eight centimeters between the points 

 of the lateral lobes, and the same from the top of the long slender petiole 

 to the point of the middle. Their consistence, though somewhat thick, is 

 not coriaceous; they are generally rounded or truncate to the petiole, and 

 marked all around the borders by short equal teeth, generally turning 

 upward; the lateral lobes are short, acute, or with a short acumen, all diverg- 

 ing 30° to 40° from the midrib, and half as long as the middle. The 

 relation of these leaves is with Acer vitifolium, Al. Br., a very rare species 

 of Oeningen, not yet satisfactorily known and characterized. Comparable 

 also with those figured as A. trilobatum by Ludwig (Joe. cit., pi. lii, figs. 

 4-6), they differ essentially by shorter, broader lobes. From the species 

 as represented by California specimens, this one differs also somewhat by 

 the less distant, smaller, less acute teeth, and thus seems a transitional form 

 between the Pliocene species and tlie European Miocene A. trilobatum. 

 Fig. 3 of our plate is merely a longer, more tapering, middle lobe. It was 

 found with a third incomplete fragment of another leaf, like fig. 1, at the 

 same locality of the Green River group, a formation intermediate between 

 the Carbon Miocene and the Gold Gravel Pliocene. 



Habitat. — Near the confluence of White and Green Rivers, Utah, with 

 Planera longifolia, Sapindus Dentoni, Myrica acuminata, etc. {Prof. Win. 

 Denton). 



SAPINDACEiE. 



SAPINDUS, Liim. 



The genus has in the present flora few species, most of them distributed 

 over the tropical regions of the globe. One species still inhabits the Southern 

 United States. The geological records refer the origin of the genus to an 

 older period than that oi Acer; at least, one of our species is described from 

 the Eocene of Golden and Black Buttes. It is there exlremely rare. From 

 Carbon group, we have one also. It is abundantly represented in the Green 

 River group, not only by comparatively numerous forms, but by a profu- 

 sion of specimens. Prof. Newberry has described two species of Sap'mdus 

 from the Miocene of Fort Union and of the Yellowstone Lignilic. In Europe, 

 twenty-one species of this genus are known, all Miocene, except a very rare 

 one described by Saporta from the Armissan. Its absence from the Pliocene 

 of California may explain its nearly total disappearance from the present 

 flora of North America. 



