92 



UPWARD GEOWTH OF THE HEAD, AND pt. ii. 



a coarse, thick, white outer coating, pointed at the 

 top. The instant the point of this tongh sheath clears 

 the earth, it opens and emits the green blade un- 

 scathed into the air. Here is again a beautiftil con- 

 trivance. The barley and oats growing from below, 

 ripened their seed, which grew when sowed. 



I have not known an instance of a garden bean 

 getting the head of its first gemmule below the wire ; 

 though, when the head was engaged above, the stalk 

 would bow down, and in this state the branch-roots 

 fixed themselves, and the plant grew, and threw out 

 new shoots from the knots and from the neck, which 

 Probable OTcw towards tlic light : and I think that the organi- 



distinot ^ ^ ^ ^ 



organisa- gatiou of thc first gcmmulc of the garden bean, and 



tion of first ® n ' 



gemmule. perhaps the first gemmule of all plants, is different 

 from the organisation of all other parts of plants. I 

 think that the reason of the death of the beans in 

 Dutrochet's beautiful experiment was, that their necks 

 and tap-roots were too far detached from the earth to 

 allow them to throw out branch-roots ; and that, had 

 they thrown out branch-roots, they would also have 

 thrown out branch-stems. 



If any of the scarlet-runners engaged their heads 

 so as to be unable to descend, they broke out, like the 

 beans, from the necks. But the heads of the gem- 

 mules of many scarlet- runners came down, grew eight 

 or ten inches horizontally across the wires to the light, 

 and then up the side of the pot diagonally to the light, 

 till they required support as usual. Some grew across 



