An Account of the Botany of the 

 Brazil Nut* 



W. J. YOUNG 



ASSISTANT, MICROCHEMICAL LABORATORY, U. 8. DEPARTMENT OF AGRICULTURE 



The genus Bertholletia, to which is assigned the Brazil nut of commerce, was 

 established in 1808 by Humboldt and Bonpland who placed it in a single species, 

 B. excelsa. A translation of Bonpland's description of the fruit of this species 

 follows. 



"Fruit a spherical, compound nut the size of a child's head and often larger, 

 divided internally into four cells each of which encloses several nuts; covered on 

 its exterior with a husk of a green color, smooth and shining. 



"Main nut very solid, rough and marked by branching furrows on its outer 

 surface, 6 lines (1 cm.) thick, divided internally into four cells by as many mem- 

 braneous dissepiments which become obliterated in part or entirely after the ma- 

 turity of the fruit, but of which there always remain traces." 



The tree is described as 33 m. high with a trunk 9 dm. in diameter. Leaves 

 alternate, oblong, subcoriaceous, 1 dm. broad and 6 dm. long, borne on short 

 petioles. Type locality, Rio Orinoco. 



On account of the great height of the trees these botanists were unable to ob- 

 tain the blossoms although it is said that they offered in vain an ounce of gold for 

 specimens. On this account they were uncertain as to the position which 

 the genus Bertholletia should occupy in the vegetable kingdom. More recent in- 

 vestigations have established its position next to Lecythis in the order Lecythi- 

 daceae, an arrangement now universally accepted. It is worthy of note also that 

 Bonpland failed to describe either the operculum or the opercular opening of the 

 fruit although the latter is shown in his drawing as becoming decidedly narrower 

 at the inner edge. 



The two species of Bertholletia: — For more than half a century after the pub- 

 lication of Bonpland's description of Bertholletia, the genus was accepted as mono- 

 typic. Evidence was being gradually accumulated, however, which was destined to 

 lead to the recognition of a second species. Among the later botanists to con- 

 tribute to this end may be mentioned Berg who, in monographing the Brazilian 

 Lecythidaceae described under the name B. excelsa a species distinct from the one 

 so named by Humboldt and Bonpland. Although Berg's description is marred 

 by several errors, it is sufficiently accurate to demonstrate that the species de- 

 scribed is not the B. excelsa of Bonpland. Berg's drawing of the fruit or pyxid- 

 ium is, moreover, quite different from that of Bonpland. 



It remained, however, for Mr. J. Miers to point out clearly the distinction be- 

 tween the two plants and to describe Berg's species under the name B. nobilis. 



The more noticeable points of distinction between B. excelsa and B. nobilis 

 are collected from Miers' description in the following summary: 



*Published by permission of the Secretary of Agriculture. 



