Germination of Seeds of Bertholletia excelsa. 
BY 
WILLIAM WATSON, 
Assistant Curator , Royal Botanic Gardens , Kew. 
With Plates IV and V. 
HE tree which yields the ‘Brazil-nuts’ of commerce is 
JL‘ a native of Guiana, Venezuela, and Brazil, where it 
forms forests in the neighbourhood of large rivers. According 
to Humboldt it attains a height of a hundred to a hundred 
and twenty feet, the trunk two or three feet in diameter, with 
large open branches bearing tufts of very close foliage at their 
summits. The trees flower in March or April, and the fruits 
ripen in about two months, ‘ forming in less than fifty or sixty 
days a pericarp, the ligneous part of which is half an inch 
thick, and which it is difficult to cut with a sharp saw.’ The 
fruit is spherical, about six inches in diameter, and it contains 
from fifteen to twenty nuts, arranged with their thin edge 
inwards. At the apex of the fruit there is an aperture half 
an inch in diameter, which is closed with a plug formed by 
the hardened calyx. Humboldt says this plug ‘ seldom opens 
of itself. Many seeds from the decomposition of the oil 
contained in the cotyledons lose the faculty of germination 
before the rainy season, in which the ligneous integument 
of the pericarp opens by putrefaction/ 
There are various explanations current as to the way the 
seeds are set free from their iron-like enclosure ; such as that 
monkeys break the shell by striking it on stones ; or that 
[Annals of Botany, Vol. XV. No. LVII. March, 1901.] 
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