Valley of the Mkumpp* 



My attention was first directed to this subject by the remarks oi 

 Muhlenburgh and Professor Bigelow,* and during my residence at 

 St. Louis 1 kept an accurate register of the time of flowering of all 

 the plants which I collected. The mean results of my observations 

 upon a few of the most common of these, I shall now compare with 

 similar ones made at Washington city,t on the coast, in latitude 

 3S° 58' N. twenty-two minutes north of the former. 



