184 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



character. Though it may be, I have here separated the leaves according to 

 the descriptions and figures of the European authors, without positively rec- 

 ognizing this distinction as legitimate; for P. aceroides and P. Guillelmce are 

 both represented by specimens from the same localities. From Goeppert's 

 figures {loc. cit.), the leaves are all much smaller than those of our plate, espe- 

 cially than fig. 3. In Heer's, however, fig. I of pi. xlvii (loc. cit.) is about 

 of the same size as ours. 



Habitat. — Carbon, Wyoming, where it is the most abundant; Washakie 

 Station, Wyoming (Dr. F. V. Hayden). 



Plalanus aceroides, Goepp. 



Plato XXV, Figs. 4, 5, 6. 



Platanus aceroides, Goepp., Fosa. Fl. v. Scbo88., p. 21, pi. ix, figs. 1-3. — Heer, Fl. Ter. Helv., ii, p. 71, pi. 



Ixxxvii, Ixxxviii, figs. 5-12, 15 ; Fl. Foss. Arct., i, p. Ill, pi. xlvii, fig. 3; p. 138, pi. xxi, fig. 



17 b; xxiii, figs. 2 fc, 4; p. 150, pl.xxvi, fig. 5 ; p. 159, pi. xxxii, figs. 1, 2. — Gaud. & Strozzi, 



Feuilles Foss., p. 35, pi. v, figs. 4-6, vi, figs. 1-3.— Lcsqx., Annual Report, 1869, p. 196 ; 1871, 



p. 290 ; Supplement, p. 11 ; Annual Report, 1H72, pp. 389, 406. 

 Platanus rngosa, Goepp., loc. cit., p. 20, pi. xi, figs. 3, 4. 

 Platanus cunei/olia, Goepp., loc. cit., p. 22, pi. xii, fig. 2. 

 Platanus (Eninghausiana, Goepp., loc. cit., p. 20, pi. x, figs. 1-3. 

 Platanus Ettingshauseni, Mass., ex p. Synops., p. 49 (pi. cit., xvii, fig. 3, xix, fig. 3). 

 Cissus platani/oUa, Ett., Foss. Fl. v. Vien., p. 20, pi. iv, fig. 1. 

 Qucrcus platanoidcs, Goepp., loc. cit., pi. vii, figs. 5,6. 

 (Juercus rotundata, Goepp., loc. dt., pi. viii, fig. 9. 



Leaves palmately trilobate, truncate or round-cordate to the petiole ; borders deeply acutely den- 

 tate, vrith unequal teeth turned upward. 



• 



As said in the description of the former species, this Platanus shows 

 a great variety in the characters of its leaves. It is the same in our living 

 species, which, on the same tree, bear leaves from three to thirty centime- 

 ters broad between the lateral lobes, and from four to twenty centimeters 

 long. The length of the petiole is equally variable, from one and a half 

 centimeters to eight; two leaves of the same size, and close to each other, 

 upon the same branch, having the petiole, one five centimeters long, and the 

 other nine. Most of the leaves taken from grown-up trees are three-, more 

 generally five-lobed, with acute divisions, the teeth of the borders being also 

 very acute, generally turned upward, and with the base truncate or broadly 

 cordate. It is only upon the young shoots growing in thickets in the gravelly 

 beds of the rivers that we see leaves scarcely lobate, or not at all, merely 

 with short, irregularly dentate borders. These represent in their outline and 

 general characters the fossil leaves described as P. Guillelma; the others 

 those of jP. aceroides. Both species may be therefore considered, in an equal 



