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present the most variable forms and greatest differences in their nervation. 

 As seen in Fig. 1, the general outline is ovate, obtuse, with the borders 

 entire or merely undulate on one side, while the other side is deeply lobed by 

 the prolongation of a basilar secondary nerve nearly as thick as the medial 

 one, branching outside with the divisions subcamptodrome. In this leaf the 

 nervation is evidently irregularly pinnate from the base of the leaf, which 

 appears rounded to the petiole ; the lateral veins are parallel on one side, 

 though at unequal distance, while on the other side the angle of divergence 

 is variable, and all the divisions are camptodrome, or rather subcamptodrome, 

 as the point of the veins passes to the borders, while some of the divisions 

 follow the borders in successive curves. Though the leaf of Fig. 2 is broken 

 on one side, it evidently shows, however, a disposition to a division by lobe 

 on the left side, where the lateral veins are less numei-ous, but thicker and 

 more branched than on the right. The division of the nervation appears 

 here to be three-palmate ; two thick opposite lateral primary nerves branch- 

 ing at a distance above the basilar borders of the leaf, rounded on one side, 

 broadly cuneate on the other, with two thinner lower veinlets on the left side 

 only. This division is platanoidal on one side, and of the Credneria type 

 on the other. In Fig. 3 the same kind of one-sided division is still evident by 

 the disposition and thickness of the lateral primary veins, which are here by 

 five, high above the border of the truncate base of the leaf, and with inferior 

 lateral thinner veinlets nearly at a right angle to the thick medial nerve. Fig. 

 4 is, too, of the same type by the one-sided division : a lobe being indicated 

 by the lateral nerve of the right side, while on the other the division and the 

 thinning of the nerve show that it ends without entering a prolongation of a 

 lobe. In this leaf the borders are cuneate to the base ; the lower lateral 

 veins under the primary ones go out of the medial nerve in the same angle of 

 divergence ; and as in the other leaves, the divisions of the lateral veins 

 are mostly camptodrome, while the secondary veins are mostly craspedodrome. 

 In Fig. 5, the three-palmate nervation is still more marked, and the extension 

 of the leaf on one side evident by the extraordinary thickness of the basilar 

 nerve on the left side. I have figured this fragment, though incomplete it is, 

 because it is the only one which shows the whole base of the leaf with a 

 petiole. The junction of the borders to the petiole is equally abnormal; 

 the leaf being on one side round cordate, and on the other round wedge-form. 

 These leaves are not referable to Platanvs or to Credneria, on account 



