MESOZOIC PLANTS PERU 57 



Schenk who discussed some of these forms at length was 

 at first disposed to consider them as ferns, as did also Brong- 

 niart, but subsequently referred them to the Cycadaceae. 

 Schimper at first adopted Otopteris but subsequently sub- 

 stituted Gtozamites. Saporta also discusses the genus at 

 length and more recently Seward has given an excellent 

 account of it. 



As at present understood it may be defined as follows : 

 Fronds pinnate, elongate. Pinnae varying in form from long 

 narrow linear lanceolate to elliptical or nearly orbicular. 

 Stipe stout, bearing the pinnae on its upper (ventral) margin. 

 Pinnae not attached by the whole base, more or less auricu- 

 late varying from rounded basal margins to conspicuously 

 auriculate, the distal lobe frequently much more prominent 

 than the proximal lobe and always more or less overlapping 

 on the stipe. Pinnae may be closely spaced, imbricated or 

 more or less remote. The area of attachment is more or 

 less broad and several bundles enter from the stipe, these 

 fork in the basal portion of the pinna and diverge in a 

 flabellate manner terminating in the distal margins. As a 

 rule branching is not obvious although it is sometimes pres- 

 ent higher up in the pinnae. The veins are numerous thin 

 and closely spaced ; their arrangement varies greatly with 

 the form of the pinnae. In long narrow forms like Otoza- 

 mites Neumanni they are practically parallel with one an- 

 other and the lateral margins and unbranched, scarcely if at 

 all distinguishable from some forms of Zamites, whereas in 

 short, elliptical, auriculate pinnae, especially when the area 

 of attachment is restricted, they are conspicuously flabellate. 



As will be realized from the foregoing the generic limits 

 are difficult to define and still more difficult to apply in prac- 

 tice. There is a natural amount of variation within the 

 different species so that the specific limits are also often diffi- 

 cult to establish, particularly when dealing with poorly 

 preserved or fragmentary material. 



