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XIV., Note on the Structure and Mode of Dehiscence of the Legumes of Pentaclethra 
macrophylla, Benth. By DANIEL OLIVER, F.R.S., F. L.S. 
(Plate XXXVII.) n 
Read November 19th, 1863. 
THE late Mr. Barter, while attached to the Niger Expedition under Dr. Baikie's 
direction as Botanical Collector, sent home from Fernando Po some remarkable legumes, 
which, under their native name of Opochala, remained undetermined in the Kew Museum 
until the recent return of Mr. Gustav Mann from Tropical Africa. Mr. Mann identifies 
these legumes as belonging to Pentaclethra macrophylla, Benth. He says that they are 
so abundant in the Island of St. Thomas that the natives collect them for fuel. The 
seeds also are edible, and afford a useful oil. 
A note by Mr. .ل‎ R. Jackson, Curator of the Kew Museums, in Simmond's * Techno- 
logist ’ (vol. iv. p. 32), referring to Mr. Mann’s identification of the legumes, has reminded 
me of some drawings which I made, in connexion with the microscopic structure and 
mode of dehiscence of these fruits, shortly after they were received at Kew, nearly four 
years ago. My object in examining these legumes was chiefly to ascertain the nature of 
the tissues which, by their contraction in drying, occasioned the valves to become very 
strongly revolute in the direction of their length. 
I have not examined a large series of fruits for the sake of comparing the mechanism 
of their dehiscence with that of the legumes of Pentaclethra; but in the few which 
1 have examined, belonging to different groups of Leguminose, I have not found any 
essential difference in the tissues which occasion the contraction and curvature of the 
valves as they dry. They differ from Pentaclethra, as from each other, in the relation 
of the contracting, thick-walled, hygroscopic prosenchyma to the parenchyma and other 
non-contractile tissues of the valves of the fruit, and especially in the quantity, form, and 
position of the bundles or layers of this prosenchyma, and also in the direction of con- 
traction and expansion, whether longitudinal or transverse with respect to its cells, and 
whether longitudinal, transverse, or oblique with respect to the valve. 0 
macrophylla is remarkable chiefly because of the large size of its legumes, and. the 
unusual extent to which its prosenchymatous bundles contract ; and as it is a rare fruit 
in Europe, and well adapted to illustrate the mechanism of dehiscence in more familiar 
instances, I have thought that it might be worth while to lay befor 8 the Linnean Society 
the details which I have noted about it, together with the drawings which I made when 
the fruit was first examined, and a few others since prepared, representing corresponding 
tissues, and their mode of arrangement, in the legumes of three -— four other genera. 
The legumes of P. filamentosa exhibit an arrangement of tissues similar to that of 
P. macrophylla, but they are much smaller. 
The legumes of Pentaclethra macrophylla in the Kew Museum measure from 22 to 
912. 
