FLORA OF THE DAKOTA GROUP. 69 



fop and undultito by the out-running of the vehis. It is triple-nerved 

 from a distance above the base, and has above the point of connection 

 of the primary nerves two or three pairs of alternate secondary veins, 

 variable in distance, straight or curved, unequally parallel, reaching the 

 borders either directly or by their branches, which by oblique branchlets 

 or by connections of nervilles at right angles form irregular quadrate large 

 meshes. There are under the primary nerves two pairs of marginal veinlets 

 with the same degree of divergence as the primary ones (40°-50°). The 

 form of this fine leaf and its mode of nervation are peculiar, and of a 

 character analogous to that of leaves described under the generic name 

 of Greviopsis in the "Sezanne Flora" by Saporta. There is, however, a 

 marked difference in the primary ternate nervation and in the entire 

 borders of the leaves. The two lower pairs of tertiary veins show also for 

 this leaf a relation to Credneria, and especially to the small leaf of Platamis 

 Heerii, pi. iii, fig. i. The secondary and tertiary nerves are of a different 

 character. 



Hah. — South of Fort Harker. Chs. Sternberg. 



Ainpelopliylluiu ovatiim, Lesqx. 



Hriyden's "Ann. Rep.." 1874, p. 355. 



Celtisf ovata, Lesqx., "U. S. Geol. Kep.,'' p. (i6, pi. iv, figs. 2, 3. 



Leaves ovate, obtuse or undulate, truncate or obtusely pointed, enlarged toward 

 the base and abruptly rounded and sub truncate or cordiforiu at base; nervation trifid 

 from the base, craspedodrome. 



Though the relation of these leaves to the preceding species is not 



very distinct, it is, however, more marked than to the leaves of Celtis. 



But for the craspedodrome, and especially the ternate primary nervation, 



they might be referable to Pojndus or Fopidites, having indeed some degree 



of affinity to P. elegans, Lesqx., "U. S. Geol. Rep.," vi, pi. iii. fig. 3. 



HAMAMELIDEtE. 



HAMAMELITES, Sap. 



Leaves membranaceous, glabrous, petiolate, oblong-lanceolate or ovate; nerva- 

 tion pinnate; secondary nerves at an acute angle of divergence, crasix'dodroine, 

 branching on the lower side; branches and subdivisions generally camptodronic. 



The leaves described in this generic division have the essential cliar- 



acters of the leaves of both Hamamelis and Alnus. 



