60 THE PEANUT— THE UNPREDICTABLE LEGUME 



in not possessing any of these distinctive features. As described by Burk- 

 art (14), Hoehne (34), and Taubert (70) Arachis differs chiefly from 

 Stylosanthes and Chapmannia in producing pegs, being geocarpic, and in 

 producing most of its flowers on the lower nodes of the stem, while 

 Stylosanthes and Chapmannia have shorter hypanthia, produce no pegs, 

 have aerial fruits, and produce most of their flowers in the upper axils. 



The genus Arachis itself, before 1839, consisted of only one species, 

 the cultivated peanut, A. hypogaea. Bentham, however, described five ad- 

 ditional species all collected from the wild in South America. Since that 

 time several additional species have been described. 



Hoehne (34,35) recognized twelve species in the genus Arachis. 

 These, with their subspecies and forms, are listed below : 



A. tuberosa Benth. A. prostrata Benth. 



A. guaranitica Chod. & Hassl. Subspecies: Hagenbeckii (Harms) 



A. Diogoi Hoehne Hoehne 



Form : typica Hoehne A. iimrginata Gardn. 



Form : subglabrata Hoehne Form : submarginata Hoehne 



Form : sericeo-villosa Hoehne A. nambyquarae Hoehne 



Form : submarginata Hoehne A. hypogaea L. 



Fovm-.minor Hoehne Forms: various 



Subspecies: major Hoehne A. glabrata Benth. 



A. angustifolia (Chod. & Hassl.) Killip Form: typica Hoehne 



A. helodes Mart. Form : major Hoehne 



A. villosa Benth. Form : minor Hoehne 



A. villosulicarpa Hoehne 



Varieties of Arachis hypogaea L. 



The dififerent forms of A. hypogaea have stimulated various workers 

 to develop varietal classifications of the cultivated peanut. Taxonomists 

 frequently resort to controversy concerning species delineation because 

 the ultimate nature of organic variation necessarily leads to intergrading 

 forms. If the species problem is difficult, the varietal problem becomes 

 nearly impossible. Yet as certain species grade into one another, varietal 

 clusters tend to assume sufficient distinctness to approximate specific 

 rank. Depending on the chance evolutionary time level at which any ob- 

 server may happen to approach such clusters, he will find himself con- 

 fronted with a continuous array of variability at one extreme or almost 

 species-distinct varietal clusters at the other. Cultivated peanut varieties 

 appear to fall somewhere between these two extremes, dififerent enough 

 to be interesting yet similar enough to be exasperating. 



In his study of the origin of cultivated peanuts, Dubard (23) suggested 

 that the forms which were transported from Brazil to the west coast of 



