8 MEMBERS OP PLANTS. 



body what the branches are to the stem, originating and 

 growing in a manner precisely similar, and increasing 

 yearly after the first year in thickness, but not in 

 length. A tuft of grass accordingly has in this way 

 been found with its root branches so much thickened 

 as to form almost a solid mass, in cases where the life 

 of the plant has been many years preserved, in conse- 

 quence of its being regularly nibbled down by sheep 

 and prevented from seeding. 



The small fibres or rootlets 1 , though an essential 

 part of a plant, may be destroyed in most cases with- 

 out causing its death, on account of their being readily 

 reproduced so long as the crown is uninjured. It is at 

 the tips indeed of these rootlets that the spongelets are 

 situated, which take up the food of the plant from the 

 soil. To prove this by Sennebier's experiment, plunge 

 a turnip or a radish in water all but its tail where the 

 rootlets grow, and it will soon wither ; place the root- 

 lets only in the water, and it will shoot out fresh leaves. 



The rootlets, like the leaves of trees that are not 

 evergreen, are produced annually ; in some cases dying 

 and falling off like leaves, as in the dahlia ; and in 

 others becoming thicker, harder, and forming radicles 

 or root branches, no longer capable of performing the 

 office of rootlets in taking in nourishment, as in most 

 trees. 



This view is beautifully corroborated by plants with 

 fibrous roots growing in loose dry sand, in which, in 

 order to procure all the little moisture possible, an 



(1) In Latin, Fibrillcs or Radicufa. 



