398 APPENDIX. 



XIX. CLASS DIOECIA. 



108. Salix.* 



The collection affords three distinct species ol Salix, 

 neither of wliich appear to agree with those known to me, 

 or the descriptions of Persoon. But they are all without 

 fructification, and cannot therefore be correctly determin- 

 ed. The first species has 



Long, linear, lanceolate, rigid, acuminate leaves, slightly 

 covered in the young ones with short sericeous hair on 

 the underside, perceptible by a lens in the old leaves like- 

 wise, they are distantly and slightly toothed in the margin, 

 of a light yellow colour on both sides, subsessile ; young 

 branches yellowish, the older red, smooth, but distantly 

 spotted with black verrucae. 



109. Salix.* 



Leaves on short petioles, narrow, lanceolate, serrately 

 dentate in the margin, smooth, green on the upper, glau- 

 cous on the underside. Approaching to Salix discolor. 



110. Salix.* 



Leaves on short petioles, ovate-lanceolate, attenuated at 

 both ends ; smooth above, densely villous below, entire, 

 or undulately crenate in the margin. Stipules apparently 

 ovate. 



Allied perhaps to S. caprea. 



111. Fraxinus sambucifolia, Pursh, p. 8. 

 Common in Pennsylvania. 



112. Empetrum nigrum, Nutt. Gen. IL p. 233. 

 In Labrador and Canada, as well as Europe. 



113. PopuLUs balsamifera, Pursh, p. 619. 

 In high American latitudes.* 



. Hah. From Pembina to Lake Superior. 



114. Shepherdia argentea, Nuttall, II. p. 240. 



