tsoMch ripen their Fruit under Ground. 397 



than, the spongiole of a root. This is more apparent when the 

 pod has penetrated the ground, and begins to develope itself, 

 decreasing in thickness as the seed which it contains approaches 

 maturity. From the point where the tubercle, or spongiole, 

 appears, there are salient lines, which mark the legume longitu- 

 dinally; and which appear to be formed of small bundles of 

 vessels, or of elongated cellules. 



These observations apply, not only to the arachis, to which 

 new and suitable organs of absorption are necessary for its re- 

 production, but to the bulb of the saffron, which essentially 

 differs but little from seed, and which is known to throw out 

 large fusiform roots from its base ; a circumstance that I con- 

 sider to afford additional support to my opinion. 



Subsequent experiments have confirmed the opinion which 

 the above observations first led me to entertain. By means of 

 a stone placed under the legume, it was prevented from pene- 

 trating into the ground, when it was found to become elongated, 

 and to try to change its direction ; but, finally, not being able to 

 reach the earth it withered and dried up. This convinced me 

 that the legumes of the arachis can never be ripened in the 

 open air. 



1 put another pod of this plant into a small empty phial, and 

 set it in a place where it could not receive the direct rays of the 

 sun. It is easy to comprehend that, while it was in this situ- 

 ation, the atmosphere within the phial was always moist ; aj;, 

 during the warm days and cool nights of autumn, the moisture 

 combined with the air in the day becomes condensed in the 

 night; and, in fact, the interior of the phial was found every 

 morning covered with drops of water. The legume was, therefore, 

 all night, and a great part of the morning, not only in an ex- 

 ceedingly moist atmosphere, but also completely battered by 

 these watery drops. This kept it growing : it elongated itself, 

 without appearing injured in doing so ; and when, in the course 

 of about a fortnight, I took it out of the phial, 1 found that it 

 was still in a fit state for penetrating into the ground. A third 

 pod, when immersed in water, became covered with a whitish 

 film ; but it lived, and elongated itself, becoming somewhat 

 thicker towards the point. I took it out of the water at the end 

 of three weeks, and found that it had still power to search for 

 the earth. The last two experiments prove that, although water 

 is not sufficient for the full developement of the fruit, it is favour- 

 able to the preservation of its vitality ; and that, though moisture 

 is a condition necessary to the production of the tubercles, or 

 roots, it is not sufficient in itself to produce them so as to enable 

 them to exercise their functions, when all other circumstances 

 are unfavourable. 



I put another legume into a phial, in which there were a few 



