178 



gret that I did not take observations on this point at the position 

 of the plant. Then, too, the ground got a good soaking, and it 

 is remarkable how rapidly the soil becomes moist for a consider- 

 able depth. Undoubtedly this fact was contributory to the rapid 

 growth of the post-pluvial foliage. In the experiment detailed 

 above, the total growth in a few days was due wholly to the water 

 available on the surface of the stem, and the inference is not 

 strained, I believe, if we conclude that, normally, the first stimulus 

 to growth in the leaves is due to the water taken up, probably, at 

 or near the buds. In view of the very thick coating of waxy 



Fk;. 2. Fotiquii I ,ii \]<l,ii,i, >i. — tlic same as in I'U;. I, tliii'e clays after a rain. 



bark it seems unlikely that the water would find entrance else- 

 where, though we may be wrong in this, since there are rifts through 

 which conceivably the water might enter. 



It may also be noted that the buds of the ocotillo arc minute, 

 sometimes indeed scarcely visible, and covered by, at most, a few 

 light-brown, thin, chaffy scales. The repeated loss of leaves at the 

 same place results in a rough area surrounding the base of the 

 bud at which water may, wc may well believe, be taken up. There 

 is otherwise no evidence of the presence of any special adaptive 



