NATURAL SCIENCES OP PHILADELPHIA. d 



The true Fraxinus americana (Linn.) is common in the public grounds 

 and on the sidewalks of some of the streets of Philadelphia. It also grows 

 along the Delaware and Schuylkill rivers in the vicinity of the city. Speci- 

 mens of it are in the herbarium of the Academy of Natural Sciences which 

 were collected in the vicinity of Boston, Mass., by Mr. Pickering, from whence 

 it extends as far south as Louisiana, the author having gathered specimens 

 of it in the woods two or three miles west of the Mississippi River, opposite 

 New Orleans. In the year 1790, William Bartram assisted in making out a 

 list of trees to be planted in Independence Square, Philadelphia. (See Penn- 

 sylvania Archives, vol. ii. p. 674.) Bartram's fondness for American trees 

 led him to select for that purpose a great variety of indigenous species, so 

 that the native trees of Pennsylvania are now well represented in this cele- 

 brated Square, among which the Fraxinus americana is conspicuous. 



Cotemporaries of Bartram, and at that time residing in the city of Phila- 

 delphia, were Zaccheus Collins and Dr. Kuhn, botanists, both pupils of Lin- 

 naeus, to whom they sent specimens, from which he described many American 

 plants, including probably the F. americana. Fraxinus pubescens 

 (Walt.) also grows in the neighborhood of Philadelphia, and, as Michaux 

 observes, there is little difference in external appearance between it and the 

 white ash. Any one who will compare the plates of these two species in the 

 Sylva will see the striking resemblance in the fruit of each, but that of the 

 red ash is shorter and more pointed. Its petioles are also more or less 

 grooved, and the under side of its leaves and the petioles and young branches 

 are much more pubescent than those of F. americana. Still the two are 

 often considered as the same species by casual observers. It grows in most 

 of the Southern States, and extends as far west as Minnesota. 



Fraxinus epiptera (Mich.) was regarded by the younger Michaux and 

 Nuttall the same as F. americana. It has been thus considered by the 

 best American botanists. Had it been different, it would have been included 

 in the Sylva by the younger Michaux. Specimens labelled by some of the old 

 botanists F. epiptera (Mich.) are now in the herbarium of the Academy, 

 and they differ not in the least from the F. americana. 



De Candolle makes F. v i r i d i s (Mich. ) a synonym ofF. juglandifolia. 

 Specimens of the latter in the herbarium of the Academy agree well with 

 those of the green ash, to which they have been referred by Nuttall and other 

 botanists. It is nearly certain that De Candolle is right, because he has been 

 able to see both Lamarck's and Michaux's specimens. The green ash grows 

 occasionally along streams from Pennsylvania to Texas. I have frequently 

 seen it on the Alabama River ; also on the Red River in Louisiana, below 

 Alexandria. It is quite common in Southern Texas, where a form of it col- 

 lected by Berlandier has been described by De Candolle as F. B e r 1 a n d i e r i i, 

 according to Torrey and Gray. Personal observation in Texas with one of 

 Berlandier's specimens, kindly sent to me by Dr. Gray, convince me of the 

 truth of their opinion. 



Muhlenberg's herbarium, at the rooms of the American Philosophical 

 Society in Philadelphia, contains a specimen of the green ash which has the 

 serrated leaves and both sides of the same shade of green, which led Dr. 

 Muhlenberg to call it Fraxinus concolor, as related by Michaux, who also 

 states that it grows abundantly along the Susquehanna, near where Dr. Muh- 

 lenberg resided. Hence there is no difficulty in determining the true F. 

 v i r i d i s , Mich., specimens of which in the herbarium of the Academy differ 

 little from his figure of it in the Sylva. Therefore the reader may rest assured 

 that the plates and descriptions in Michaux's Sylva of Fraxinus americana, 

 F. pubescens and F. viridis are correct. 



Since the time of Michaux, the American forest trees have rarely been care- 

 fully studied by botanists, because they are apt to look on the ground for new 

 plants and flowers, and not up at the trees. Even Nuttall, in his travels, gave 



1862.] 



