398 



MEMOIRS OF THE XEW YORK BOTANICAL GARDEN 



Betula lutea was listed from the Ottawa valley by Pen- 

 hallow," in a report on the Pleistocene flora of the Don Valley, 

 Canada, hut witliout any description or illustration. 



Genus Alnus Hill 

 Alnus sp. 



Plate 31, figure 2 



"Alnus n. spJ" HoUick, Summary Kept. {loc. cit.), p. 134. 



This fragmentary specimen represents a piece of the upper 

 portion of a leaf that is suggestive of the obovate forms of sev- 

 eral existing American species of alder, such as Alnus serrulata 

 WilldenoAv, A. fruticosa Ruprecht, and A. ohlongifolia Torrey, 

 and the Old AVorld species A. rotundifolia Miller {= A. gluti- 

 nosa Miller) — especially the last, which is a common element in 

 the European Pleistocene flora. This was also described by 

 Reid," based upon identification of seeds, from deposits re- 

 garded as Pliocene in age, and by Marty,^- based upon folial 

 identifications, from deposits regarded as of Miocene age. In 

 particular our specimen may be compared wdth the similar large 

 fragmentary one represented by Marty's figure 2, plate 3 {op. 

 cit.) ; and except for its much larger size it is suggestive of speci- 

 mens from the Pleistocene (Talbot formation) of Maryland, de- 

 scribed and figured by the writer" and referred to the existing 

 eastern North American species Alnus rugosa K. Koch {= A. 

 serrulata Willdenow). Our specimen, in its entirety, was appar- 

 ently obovate in shape, with a somewhat uneven or wavy margin, 

 finely dentate, the dentitions consisting of an obscurely defined 

 major series with minor denticulations between. Its fragmen- 

 tary condition renders impossible either a specific description 

 or a positive identification that would be of any value. 



10 Penhallow, D. P., in Dawsou, Penhallow and others. Canadian Pleistocene 

 flora and fauna. British Assoc. Adv. Sci., Eept. Sec. C, Bradford meeting, pp. 335, 

 338. 1900. 



11 Eeid, Eleanor M. Two pre-glacial floras from Castle Eden. Geol. Soc. 

 [London], Quart. Jour. vol. 76, pt. 2, p. 118, pi. 8, fig. 1. 1920. 



12 Marty, Pierre. Flore Miocene de Joursac (Cantal), p. 27, pi. 2, fig. 11; pi. 3, 

 figs. 1, 2. 1908. 



13 HoUick, Arthur. Md. Geol. Survey, Pliocene and Pleistocene, p. 225, pi. 69, 

 figs. 1-3. 1906. 



