124 THE FLORIST AND 



be no greater than that of other shade trees of equally rapid growth. Ther© 

 would indeed appear to be no valid objection to the extension of this tree ? 

 were it not for the odor of the blossoms, which in the month of June fills the 

 air in the neighborhood of the trees, is exceedingly offensive to many per- 

 sons, and hence probably has been deemed prejudical to the public health*. 

 The objection cannot however obtain against all Ailanthus trees, for the plants 

 being in the language of Botanists dioicious, bears its seed upon one tree, 

 and its barren pollen-yielding flowers upon another. The seed-pro duciag 

 tree is not in the least offensive, and had it been exclusively planted, the ob- 

 jection now being considered, could not have been urged. Examples of these 

 seed-bearing trees may be found in many of our streets, Seventh St. and 

 Eighth St., west side, immediately above Walnut, are familiar localities. Un- 

 fortunately, and probably from circumstances purely accidental, the pollen- 

 iferous tree has been generally planted, and to the volatile oil contained m 

 its flying pollen may the odor be ascribed. 



We have in vain sought proof that this pollen is detrimental to public 

 health. Plausible causes have been stated, but these when sifted out have 

 been found destitute of foundation. They appear to have gained credence 

 from the common error of mistaking events merely contemporaneous, for 

 cause and effect. The College of Physicians of this city, a Society composed 

 of the most sugacious and observant members of the faculty, and at the 

 meetings of which, the causes, phases, and march of disease within our bor- 

 ders, are closely discussed, has not in its " Transactions," the record of any 

 case aggravated or otherwise influenced by the tree in question. 



We admit that such evidence is but negative, yet we contend tha& as far 

 as observation has gone it is conclusive, that the Ailanthus is not injurious 

 to health, That the odor is offensive to many cannot be questioned, yet the 

 dislike is by no means universal : and it might not be improper to suggest 

 that there exist in various parts of the City, filthy sources of undoubtedl y 

 insalubrious odors, which ought to be abated. 



We believe that a public statement of the entire inoffensiveness of the 

 seed-bearing tree, especially if made by the high [authority of the City 

 Councils, would eventually lead to its general introduction in place of its bar- 

 ren consort. A. L. K, 



THE GENUS FRANCXSCEA. 

 Amongst the species constituting this genus of tropical shrubs are includ- 

 ed some of the best hothouse plants in cultivation. Indeed few pre better 

 deserving of assiduous attention, or produce a more pleasing effect* when well 



