FOSSIL FLOUA. 735 



morphian, l)ut differs in being nuidi larger and in luiving more numerous 

 and closer secondaries. It is midoubtedly close to this species, and rather 

 than make it a new species I have referred it to this. 



Haliitat: Yance\' Fossil Forest, near the standing trunks; collected 

 by F. H. Knowlton, August, 1888. 



ACERACE.E. 



ACEK VIVARIUM n. Sp. 



PI. XCVIII, tig. 4. 



Leaf membranaceous, palmately o-lolied, narrowed below to a wedge- 

 shaped base, sinuses rounded, middle lobe lanceolate-acuminate, as long- 

 or longer than the body of the blade below the sinuses; lateral lobes 

 at an acute angle (points not preserved): margins remotely toothed with 

 small, sharp, upward-pointing teeth; midrilj, or central rib, strong, straight, 

 slightly stronger than the lateral ribs, which arise from the midrib just 

 above the base of the lilade at an angle of al)out 70 ~ and ^tass up straight 

 to the points of the lateral lobes or cur\e slightl}' outward; lateral ribs 

 with several pairs of secondary branches, those on the outside beginning 

 just above the base of the blade and passing straight or with a slight 

 upward curve to or entering the teeth; secondaries on the u^Jper or inside, 

 beginning- below the sinus, which the lowest one enters, the others probably 

 entering the teeth: middle lolje with al)oat 6 pairs of alternate second- 

 aries arising at an angle of 70° or 75°, and passing up nearly straight, to 

 end in the teeth or fork just below the teeth, one branch entering and the 

 other going upward near the margin to the one above; ner-sdlles numerous, 

 mainly percurrent; finer nervation beautifulh" pi-eserved, forming quad- 

 rangular areolae. 



The example figured is tlie only one observed of this species. It is 

 about 10 cm. long and (i cm. broad. The central lobe is aljcmt f) cm. long 

 and a little more than 2 cm. wide. The lateral lobes appear to have been 

 about 2 cm. wide and of an luiknown length. 



This leaf belongs to the Acer trilobatum group, so many forms of which 

 were described by Heer from the Swiss Tertiary. In shape it is most like A. 

 trilobatum prodiictuiii ,^ but differs in having only very small, sharp teeth. It is 



' Fl. Teit., Helv., yol. Ill, PI. CXV, figs. 6-12. 



