THE ORDEAL BEAN OF CALABAR. 241 
suborder Papilionacee and tribe Phascolee ; but subordinate to this, 
its characters have been considered sufficiently peculiar to warrant the 
formation of a special genus for its reception. This has accordingly 
been done, the new genus receiving from Dr. Balfour the name of 
Physostigma,* and the one species which it contains, that of venenosum. 
The most remarkable character of the genus Physostigma is that de- 
rived from the stigma, which possesses a singular, crescent-shaped, 
hooded appendage. By this character and the long grooved hilum of 
the seed, it is separated from the nearly allied genus Phaseolus ; and 
from Mucuna, to which its seed bears considerable resemblance, by t 
characters of its flowers and pod; from Canavalia by its diadelphous 
stamens and other characters ; and from Lablab, by its phaseoloid carina 
and its pistil. 
Physostigma venenosum, the Ordeal Bean, is a large climbing peren- 
nial with a woody stem of two inches diameter and sometimes fifty feet 
in length. Its large leaves are pinnately trifoliolate, with ovate acumi- 
nate leaflets. Its papilionaceous flowers are in pendulous racemes, the 
stalk or rachis of which is covered with tuber-like knots; each flower is 
about an inch in length and of a pale-pink or purplish colour, beauti- 
fully veined. The legume when full-grown is about 7 inches in length, 
elliptico-oblong with a short curved point, stipitate, dehiscent and con- 
taining two or three seeds. The seeds, which are oblong or somewhat 
reniform, are from 1 to 13. inches in length by about $ of an inch in 
breadth; their convex edge marked by a long sulcate hilum, extending 
as a deep furrow from one extremity of the seed to beyond the other. 
The exterior of the seed is somewhat rough, with a dull polish ; its 
colour is a deep chocolate-brown, somewhat lighter on the raised edges 
of the furrow. The seeds weigh, on an average of twenty, 67 grains. 
The Ordeal Bean is difficult to obtain even near the localities where 
The genus is thus defined :—Calyx 
From gucdew to inflate, and otiypa. 
campanulatus, apice esd a laciniis brevibus, lacinia suprema bifida. Corolla 
trescentiformis, papilionacea ; vexillum reeurvum, apice bilobatum, basi alan. 
margine utroque auriculatum, membrana inflexà auctum, medio longitudinaliter bi- 
ums ; to-oblongæ, li , supra carinam conniventes, versus basin 
appendiculatæ. Discus vaginifer. Ovarium stipitatum, 2-3.ovulatum. Mn t 
ariua tortus, infra stigma subtus barbatus; stigma o insu, cucullo cavo oblique 
ehiscens, oligospermum, elliptico-oblougum, subcompressum, 
extus rugosum, arpium intus telå laxå cellulari tectum, isthmis cellulosis inter 
Semina strophiolata, hemisphærico-obl nga, hilo late suleato semicincta = 
Herba sw ruticosa, volubilis, in A dentali tropica crescens: foliis pinnatim 
VOL, I, R 
