324 SECOND FORAMEN IN FABA VULGARIS. 
I should be glad to know if any other hybrid plants separate again 
into their two parental conditions. 
ON THE EXISTENCE OF A SECOXD FOEAMEN IN THE 
LEGUME OE FABA VULGARIS. 
By Authur B. Church, M.A. Oxon, r.C.S. 
In the 'Journal of Botany' for April, 1864^ I announced the exist- 
ence of a small foramen towards the proximal end of the ventral sutu.re 
of the pod in several leguminous plants^ notably in the common Field 
Bean. At the same time I suggested that the drying of the pod, with- 
out dehiscencCj took place in virtue of this opening. I had observed. 
however, that the drying of the pod in Faba vulgaru as often begins 
at the distal as at the proximal extremity, and therefore searched for 
the cause of this j>henomenon by carefully examining the further end 
of the pod. The existence of a second opening, at the point of the 
beak, was soon detected. This newly observed foramen generally ap- 
pears before that at the proximal end of the legume ; both originate 
in the shrinking and drying up of the adjacent tissues, which are par- 
ticularly thin near the sites of the foramina. 
The physiological function of these openings is evident, but their 
significance in systematic botany still remains to be investigated, I 
proposed the term aeropyle for the opening first discovered \ that now 
described may be distinguished as the distal aeropyle, the epithet 
proximal being applied to the former. 
That the aeropyles are really in communication at once with the 
external air and with each other is beautifully seen in the following ex- 
4 
periraent. Eemove a ripe undehisced pod of F. vulgaris from the plant ; 
plunge the "beak" under water, and having placed the lips round 
the other part of the pod blow gently through it. A slight pressure 
of the breath will suffice to cause air to enter at the proximal aeropyle, 
to travel through the pod, and to pass out as a rapid chain of bubbles 
from the further air-gate into the water; no air escapes elsewhere. 
