90 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



Order ARISTOLOCHIACE^E. 

 Aristolochia cordifolia Newb. 

 PI. XXXIX ; XL, fig. 7 ; LX, fig. 4. 



Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 74; Ills. Cret. and Tert. PI. 



(1878), PI. XXII, under Catalpa crassifolia; XXV, fig. 7. 

 Catalpa crassifolia Newb. Op. cit., p. 56. 



"Leaves large, fleshy, ovate, heart-shaped at base, pointed above, 

 sometimes unsy mmetrical ; margins entire; nervation strongly developed; 

 midrib straight or flexuous; lateral nerves about seven pairs; lower pair 

 strongest, not reaching the middle of the leaf, giving off each about four 

 branches on the lower side, of which the lower ones spring from the base 

 of the laterals and are much branched; upper laterals branched at their 

 summits, branches uniting to form a festoon somewhat remote from the 

 margin; tertiary nervation invisible." 



Collected by Dr. F. V. Hayden. 



These leaves are referred in the Annual Report of the New York 

 Lyceum of Natural History with hesitation to Catalpa, which they consid- 

 erably resemble in form and nervation; but a large number of specimens 

 submitted to inspection since the description was written exhibit characters 

 which lead me to suspect that they represent a species of Aristolochia. 

 This additional material shows the leaves to have been sometimes very 

 large, more than 1 foot in diameter, broadly cordate in outline, often 

 unsymmetrical. Fig. 4, given on PL LX, exhibits the broader and more 

 rounded form and the open festooned nervation; but this is scarcely more 

 than one-third of the linear dimensions of the largest. The texture of 

 the leaf seems to have been very thin, the nervation is sparse and open, 

 though the principal nerves must have been somewhat fleshy. There 

 are also associated with these leaves slender tortuous stems that seem to 

 be portions of a vine. Taking these facts into consideration, I have been 

 led to refer these leaves to Aristolochia and to compare them with the 

 large, broadly cordate leaves of A. sipho. Future collections will undoubt- 

 edly furnish material which will render it possible to speak with confidence 

 in regard to the generic relations of the plant. 



Formation and locality: Tertiary (Eocene f). Banks of Amil Creek, 

 Dakota. 



