DESCRIPTION OF SPECIES— MORE^. 207 



species of Aristolochia, have distinctly the same essential characters as those 

 of F. planicostata and F. tilicffolia, and represent tlie same type. They appear 

 to be as profusely distributed at some localities as F. planicostata is at Black 

 Buttes. 



Habitat. — Six miles above Spring Canon, Montana {Dr. A. C. Peale); 

 lately obtained by the same geologist from north of Grand River, Colorado. 

 It is not rare at Golden, Colorado, where the fine specimen of fig. 5 was found. 



Fit-. IIS asarifoMa, Ett. 



Plate I.XI, Figs. 18-21. 



Ficnis aaarifolla, Ett., Foss. Fl. v. Bil., p. gO, pi. xxv, figs. 2, 3.— Scbp., Pal. V^g(?t., ii, p. 743.— Lesqs., 

 Annual Report, 1872, p. 378; 1674, p. 303. 



Leaves petioled, broadly reniform, sulieordate or subpeltate, rounded upward; borders crenulate, 

 primary nerves palmately tive to seven, tbe middle ones straigbt, tbe upper lateral ones somewbat 

 stronger tbau tbe lower, curving inward, brancbing and anastomosing witb tbe brancbesof tbe middle 

 nerve, wbicb are few and distant from tbe base; veinlets tbick, transversal, forming by subdivisions 

 an embossed-like, very distinct, polygonal areolation. 



Though this species has been already briefly described from specimens 

 found at Golden, it has not before been figured, the first fragments obtained 

 being all too incomplete. It is, however, recognized easily by its peculiar 

 nervation, forming in its subdivisions small, elevated, polygonal areolae, which 

 give to the surface the appearance of a very small embossed check-board, like 

 that of the leaves of Asarum Europeum. The meshes are mostly equilateral or 

 nearly square along the borders, more or less and irregularly expanding out- 

 side, and thus forming crenulations more or less distinct, according to the 

 size of the leaves. The fragments from Golden represent much larger leaves 

 than those described in the Flora of Bilin. Those figured here, from spe- 

 cimens of Point of Rocks, are perfectly well and entirely preserved, and 

 rather smaller than those of Europe. They are also slightly more enlarged 

 on the sides, or renilbrm, and the crenulation is scarcely di!>tinct. But the 

 border divisions are, for their expansion, related to the areolation, which is pro- 

 portionate in size to that of the leaves. The American leaves are evidently 

 either peltate or auricled, as seen in three of the figured specimens. One only 

 has the base and the attachment of the thick petiole marked similarly to that 

 of the European leaves; but even the figures of the Biliu Flora seem to indicate 

 peltate leaves, whose borders are erased at the base or at the point of attach- 

 ment of the petiole. Fig. 21 of our plate also has a short, thick, flat petiole, 

 only one centimeter long; but it is evidently broken. These differences are 

 unimportant, and cannot be considered as specific characters. Our leaves, 



