DESCRIPTIONS OF SPECIES. 103 



We have here in the specimens which are figured and others similar, 

 representatives of a fine species of Platanus which is apparently distinct 

 from any hitherto described. In general form it most resembles P. Haydenii 

 Newb., and may prove to be only a variety of this species; but the leaves of 

 P. Haydenii obtained in Wyoming have only an undulate or bluntly toothed 

 margin; it is well known, however, that this is a character which is exceed- 

 ingly variable, and specific distinctions can hardly be based upon it. How- 

 ever, the marginal teeth shown in figs. 1 and 2, the base and summit of the 

 leaf, are so peculiar in their size and their compound character that without 

 connecting links we should not be justified in uniting these leaves with any 

 others. In fig. 3 of the plate cited it will be noticed that the dentation at 

 the base of the middle lobe is smaller and more like that in P. Haydenii, but 

 the margins in this specimen are so incomplete that they afford information 

 of but little value. Its chief importance is its demonstration of the large 

 size and distinctly trilobate outline of some of the leaves of this tree. 



The leaf figured in PI. XLIV, fig. 5, presents a marked difference of 

 form from those represented on PI. XLII, but the character of the margins 

 is the same, and it seems probable that this is only the ovoid form which 

 the young and some of the mature leaves are prone to assume. Until 

 further light shall be thrown on the subject it is safest to consider all the 

 leaves mentioned in this note as belonging to the same species. 



Formation and locality: Tertiary (Miocene). Bridge Creek, Oregon. 



Platanus Haydenii Newb. 

 PI. XXXVI; XXXVIII; LVI, fig. 3. 



Ann. X. Y. Lye. Xat. Hist., Vol. IX (April, 1868), p. 70; Ills. Cret. and Tert. PI. 

 (1878), PI. XIX; XXI. 



"Leaves large, long-petioled, when mature three, perhaps rarely five 

 lobed; lobes nearly equal, long-pointed, acute; on either side of the mid- 

 dle lobe five to eight obtuse teeth; margins of the lateral lobes sinuately 

 toothed to near the base; younger leaves ovate, acuminate, coarsely toothed 

 throughout, except near the base, which is slightly decurrent; nervation 

 strong, radiate from the base, primary nerves three, which are nearly 

 straight, and terminate in the three lobes of the border. From the midrib 



