of Arachis and Voandzeia. 157 
except that the calyx is rather less deeply divided ; they are also usually sterile ; 
at least, after examining several flowers of seventeen or eighteen species, I have 
only once observed a tendency on tbe part of the style to separate itself from 
the ovarium, whilst I have continually seen this organ wither and fall off with 
the calyx. The fertile flowers of Stylosanthes also resemble Arachis in the 
most important peculiarity that they are entirely without floral envelopes. The 
ovarium is, however, nearly sessile between the two bracteolæ, which always 
exist in both genera, and it is terminated by a short hooked style with a 
somewhat thickened stigma. During maturation it swells and separates into 
two articulations, without any elongation of the torus. 
It is not impossible that the hermaphrodite flowers of Stylosanthes may also 
be occasionally fertile, but the hook which constantly terminates the legume 
seems to show that it proceeds from the hooked style of the naked flowers, 
and not from the straight end of the ovary of the perfect ones. 
The chief point in which Arachis differs from Hedysareæ is in the legume, 
which does not separate into distinct articulations, a character regarded as ab- 
solute in all Hedysarece with more seeds than one; and this is the reason that, 
notwithstanding the remarkable resemblance of the flowers to those of Stylosan- 
thes, no one has as yet, to my knowledge, proposed bringing them together ; 
but even in this point it will, perhaps, be found that Arachis is nearer to He- 
dysareæ than to any other tribe. As in the Hedysaree, it has no valvular 
dehiscence, and its surface is marked with those remarkable reticulations, 
which, as far as I am aware, are peculiar to Hedysareæ ; the young legume is 
often very much constricted between the seeds; and even the non-articulation 
may be accounted for by the underground maturation, a circumstance which 
has usually the effect of rendering indehiscent the underground legumes in 
amphicarpous species of which the upper legumes are dehiscent. 
Voandzeia resembles Arachis in having sterile perfect flowers and apetalous 
fertile ones, which enter the ground to ripen the legumes, it has therefore 
been usually associated with Arachis; and I myself, when studying Phaseolee 
at Vienna, having no specimens of Voandzeia at the time, referred it with 
Stylosanthes to Hedysareæ: but in this I was mistaken; the underground 
fruits of most amphicarpous Leguminosc proceed from apetalous flowers, so 
that that character alone would not connect Voandzeia with Arachis any more 
VOL. XVIII. Y 
