412 



MEMOIKS OF THE XEW YORK BOTANICAL GARDEN 



cum and A. torontoniense. Those leaves (see plate 47) I have 

 reproduced, natural size, from i)hotographs of the original spec- 

 imens, kindly transmitted to me by Prof. J. H. AVhite, of the 

 University of Toronto. They represent the figures of the two 

 species as originally dejncted, reduced in size, by Penhallow, in 

 the American Naturalist {loc. cit.). Our figure 1 represents his 

 single figure of A. pleistocenicum, and our figure 2 the lower 

 one of his two figures of A. torontoniense. The closer these 

 specimens and photograi^hs were studied, and the more exten- 

 sively they were compared with species in the genera Acer and 

 Platanus, the more certain it appeared tliat an error had been 

 made in referring them to the former genus, and the more likely 

 it appeared that their true generic relationship was with the 

 latter. It may, indeed, be inferred that if Penhallow had not so 

 referred them they would have been generally accepted as rep- 

 resenting the genus Platanus and both, perhaps, merely as vari- 

 ant forms of P. occidentalis. The latter species was listed {loc. 

 cit., American Naturalist, p. 448) as an element in the Pleisto- 

 cene flora of the Don Valley and elsewhere, but no specimen 

 recognized as referable to either Acer pleistocenicum or A. to- 

 rontoniense has been recorded from any locality other than the 

 Don Valley. 



In the course of correspondence had with Professor White, in 

 relation to the specimens from the Don Valley, he referred, 

 under date of February 3, 1913, to the two species in question 

 as follows : " . . . I find I cannot see eye to eye with Penhallow 

 in some of his identifications. . . . Penhallow 's list is peculiar 

 in containing but tAvo extinct species, Acer pleistocenicum and 

 A. torontoniense. ... I should prefer to call both the above 

 Platanus." 



In the circumstances I am inclined to regard the leaves that 

 are included in these two species as rejDresenting a type of Pla- 

 tanus leaf that is characteristic of the Pleistocene of the Don 

 Valley, and to utilize them for comparison with our much larger 

 leaves from the Saint Eugene silts ; and such comparison indi- 

 cates that while the leaves from the two localities are apparently 

 congeneric they must be regarded as specifically distinct and, 



