Field and Forest. 41 



marked upon Q. nigra. Its union with Q. coccinea var. tinctoria, 

 rests on a mucli surer basis. Two trees whicli I have recently dis- 

 covered in a wood near the nortliwestern corner of the Distri6l of 

 Columbia, growing in a wild state, have proved unusually interesting. 

 That these should be called Q. Leana and not Q. heterophylla, I main- 

 tain for the following reasons : Their resemblance to Q. heterophylla, 

 as it exists in the herbarium of the Department of Agriculture, is not 

 sufficiently close to warrant this name, the leaves being broader and 

 less lobed. They do agree substantially with the specimens of Q. 

 Leana in that herbarium. They also agree remarkably well with the 

 tree which Mr. W. R. Smith, Superintendent of the U. S. Botani- 

 cal Garden has raised in his grounds from an acorn of Q. imbricaria. 

 Finally on considering the locality in which these trees were found 

 it seems impossible to believe that Q. phellos can have* entered into 

 the combination. In the entire wood where they are situated not an 

 individual of that species exists. It is wholly wanting throughout the 

 region of Rock Creek on which the grove is located. On the-con- 

 trary the prevailing oak there is Q. imbricaria, although both varieties 

 of Q. coccinea are also frequent. It cannot therefore be justly claimed 

 that this new discovery constitutes a revival of the famous Bartram's 

 Oak, since this was decided on the highest authority to be either "a 

 form of Q. phellos'''' or a union of that species with Q. coccinea var. 

 tinctoi'ia. It is, however, none the less a botanical curiosity. 



Next in point of interest may be mentioned the supposed union of 

 Q. nigra with Q. coccinea, var. tinctoria. This tree I found in a 

 grove of second growth timber lying east of the city. Its leaves most 

 resembled those of the latter species but exhibited the rusty-pubes- 

 cent under surface characteristic of the former with considerable 

 prominence. The acorns, however, which were very abundant, were 

 in all respects those of Q. nigra. Its habit was also that of this spe- 

 cies of which several trees stood in immediate proximity to it. 



Lastly there is constantly manifested a tendency on the part of Q. 

 falcata and Q. palustris to shade off into each other. This happens 

 by a mutual convergence of the two species, both as respects leaves 

 and acorns, so that while an exact medium might be difficult to find, 

 the suspicion is none the less strong that each is capable of impressing 

 its stamp upon the other in more or less marked degrees. 



The following tabular exhibit of the oaks of the Potomac side, so 



