32 



ON THE OWALA OR OPOCHALA. 



BY JOHN B. JACKSON. 



In the 3rd volume of the Technologist, at p. 155, is an account of 

 the " Owala," or " Opochala" of Western Africa, and of the oil which is 

 yielded by its seeds. At the time that article was written, little was known 

 of the habits of the plant, and consequently the native name was all the 

 clue that could be had, with the exception that from the form of the 

 pods, seeds, &c, it was clearly seen to belong to the Leguminous order. 

 Since then, however, Mr. Gustave Mann, the zealous botanical collector 

 to the Royal Gardens, Kew, who has spent three years in West Tropical 

 Africa, has identified it with the Pentaclethra macrop/iy}la,~Beiith., belonging 

 to Leguminosse, sub order Mimosese. It is a large and handsome forest 

 tree, with bipinnate leaves 2-3 feet in length, made up of many trapezi- 

 form leaflets, each about an inch long, and the small flowers arranged 

 in a spicate manner on the branches of a terminal panicle. The pods 

 in the Museum of the Royal Gardens, Kew, which are those sent home 

 by the late Mr. Barter, are not only, as stated in the paper before alluded 

 to, 1 foot long, but quite 2 feet, and this, I understand, is about the 

 ordinary length, the widest part three inches, and the thickness of the 

 entire pod about 1 inch. The seeds lie in an oblique direction. One of the 

 most peculiar things connected with the pod is the extraordinary strength 

 of the fibrous tissue of which it is composed. The valves are each a 

 quarter of an inch thick, made up entirely of this strong fibrous sub- 

 stance, the fibres running longitudinally. When ripe, the two valves 

 burst open with a loud report, scattering the seeds, and, at the same 

 time, each valve contracting and curling round in opposite directions. 

 So great is this power of contraction, that if the pods be bound round 

 with strong wire at the distance even of two or three inches apart, it 

 frequently bursts between its bands as if overloaded inside, but in all 

 cases the membranous lining of the pod always remains uninjured. 

 This peculiar habit of contraction was first brought to my notice as the 

 pods were lying amongst other specimens of fruits, seeds, &c, which 

 had been recently brought from a cold room into a warm one, by a 

 motion at intervals amongst the whole collection. Upon examination, 

 I found that the apparent vitality was in the pods of the Pentaclethra, 

 the valves of which were gradually rolling themselves into a much 

 smaller compass, of course upsetting the other things by their move- 

 ments. 



The seeds, besides yielding the oil alluded to, are collected at the 

 seasons of their falling, and eaten as food by the natives of Fernando Po. 



Kew, July 11, 1863. 



