THE 



AMERICAN NATURALIST. 



Vol. xvi. — AUGUST, 1882. — No. 8. 

 ON THE COMPASS PLANT. 



BY BENJAMIN ALVORD. 



CINCE the publication of my paper on the compass plant, 

 ^ Silphium laciniatum (see page 12 of " Proceedings of Ameri- 

 can Association for Advancement of Science at Cambridge, Mass., 

 in August, 1849"), I have made no communication concerning 

 it to any scientific journal, constantly hoping that my army sta- 

 tion would bring me where I could make more satisfactory ex- 

 periments. In the meantime it has been made the topic of sev- 

 eral papers (about fourteen in all) which will be enumerated at 

 the end of this article. 



The Silphium laciniatum is a perennial plant of the order Corn- 

 posits ; the first year it bears only radical leaves, the second year 

 and after, it is a flowering herb with four or five leaves on the 

 stem; very rough bristly throughout; leaves pinnately parted, 

 petioled but clasping at the base. Root very thick. Flowers 

 yellow. Found on rich prairies of the Mississippi valley from 

 Minnesota to Texas, not found on the Pacific slope. Stem stout, 

 trom three to five feet high; leaves ovate in general outline, from 

 twelve to thirty inches long. 



It was first seen by me in the autumn of 1839, on the rich 

 Prairies near Fort Wayne in the north-eastern portion of the 

 Cherokee nation, near the Arkansas line. I felt assured that its 

 curious properties had not b«>en made known to the scientific 

 world, and after I had explored 'all those regions on horseback, 

 and satisfied myself of the verity of the peculiarity, I made it 

 known to the National Institute in Washington, the officers of 

 the army having been requested by that enlightened Secretary of 

 W ar, Joel R. Poinsett, to aid that society as opportunity should 



