MEMOIRS 
OF THE 
TORREY BOTANICAL CLUB. 
Vol. IV. No. 4. 
Arachis hypogaea L.* 
Bv ANNA STOCKTON PETTIT. 
( PLATES 83-85.) ' 
* Submitted in partial fulfillment of the requirements for the degree of Doctor of 
Philosophy, in the University Faculty of Pure Science, Columbia College. 
History. 
The study of this plant was undertaken for the purpose of dis- 
covering, if possible, some additional facts concerning its habit of 
ripening fruit under ground. Other species of the Legumi- 
nosae are known to share this peculiarity with Arachis. Among 
the best known of these are Vicia amphicarpa and Trifolium sub- 
terraneum. Vicia amphicarpa bears two kinds of flowers and ac- 
cordingly two forms of fruit, only one of which is developed under 
ground. The flower which gives rise to this fruit is formed and 
always remains underground. The other form of flower and fruit 
is developed normally, so that in this case the peculiarity of the 
plant lies as much in its underground flower as in its underground 
fruit, as the latter seems to be a natural sequence of the former. 
Trifolium subterraneum bears but one kind of flowers. These 
are developed in heads. After flowering, the peduncle bearing 
the head sinks to the ground and, continuing to lengthen, pushes 
the head under the soil. The seeds will ripen above ground, and, 
according to Belli, if the heads are prevented from going into the 
earth, the seeds germinate easily if the integument is broken; 
otherwise the germination takes place with difficulty. 
