448 



THE A M ERICA X NA TUHALIST [\or.. XLI 



anv ])revi(Mi^ collection from the Don. tlie leaves contained in the 

 im'sent one are sudiciently characteristic lo make the determiu- 



Platanus occidentalis L- ( )ne small and imperfect leaf shows 



represented, this tret^ lia> neverthele>> been louml in a ])r(>\i()ns 

 collection representino' two localities, and it is a recoiini/ed con- 

 stituent of tlie Don Hora. 



IloUick ('()(>, 231, 232) ha. ^hown die occnrrence of P. acrroidr, 

 Goepp., together with another lar-e leaved bnt nnnamed si)ecies, 

 in the Sumlerland Formation of Maryland. 



Populus grandidentata Michx. This w(>ll known hnt sparingly 

 represented species is a well recognized clement of the Don flora, 



Prunus sp.— The genus is represented in the present instance hy 

 a single drupe of an oblong form. A similar but somewhat slu)rt(M- 

 fruit has been found on one previous occasion. 



Quercus alba I..— The white oak is represented in the present 

 collection by fragmented but well characterized leaves. This 

 species has been observed previously in only one collection. The 

 specimens obtaiiu.! from (^.aol Hill were so imperfect as to make 

 the determination open to some (|nesti()n, but the present material 

 is suffieientlv pcrfc<i to vvmovv all <lonbt. 



Other oak leave, arc also (Mni>raced in the 1906 collection, but 

 the fragments are too incomplete^ to justify reference to a particu- 

 lar species. It is <iuite probable that they may represent the 

 white oak, l)ut this cannot l)e stated with any degree of certainty 

 since the Don flora embraces no less than seven recognized species, 



the second time it has been fountl. 



