184 



HUTCHINSON'S POPULAR BOTANY 



their length, and look like a bundle of spindle-shaped (fusiform) roots 

 (fig. 229). 



We might tabulate the chief forms of subterraneous roots in the following 

 manner : 



fl. Conical. 

 -J2. Fusiform. 

 ' (.3. Napiform. 



FIBROUS 

 BOOTS 



"f 



1. Non-tuberous. 

 Tuberous 

 a. Moniliforin. 

 l>. Nodulose. 

 c. Annulated. 



fl. Tuberous Fas- 

 QUASI - cicular. 



FIBROUS-* Tuberous Tes . 



ROOTS - I ticular. 



Many perennial plants of the rosette type, which like to keep their 

 leaves flat on the ground to be safe from extirpation by browsing animals, 

 develop a special set of roots whose function is to pull the plant down into 

 the soil to counteract the growth of the root-stock, which would lift them 

 above the proper level. These hauling roots go down into firm soil and 

 take hold of it ; then by contraction they pull the whole plant down 



sufficiently. But how do these special roots 

 know when the proper level for the root- 

 stock has been reached ? 



Certain plants with spreading fibrous 

 roots subserve a useful purpose by binding 

 together the loose sand on the seashore, and 

 raising those banks which, as in Norfolk, 

 defend the country from the encroachments 

 of the sea. Of this sort are the Lyme-grass 

 (Elymus arenarius), the Sea-sedge (Carex 

 arenaria), the Marram (Psamma arenaria), 

 and the beautiful Sea-holly (Eryngium 

 maritimum). 



The Marram, mentioned above, was the 

 subject of an Act of Parliament in Queen 

 Elizabeth's time, the purpose of the Act 

 being to encourage the cultivation of this 

 grass and prevent its destruction. Its 

 preservation is still carefully provided for 

 by the " bank-reeves." 



The dunes on the shores of Holland and 

 Denmark have been an object of care by 

 the Government for an even longer period 

 than have the English dunes ; and there, 

 also, resort is had to the cultivation of 

 grasses and creeping plants, while burrowing 

 and grazing animals are rigidly excluded. 

 FIG. 236. ANNULATED ROOT OF In certain parts of France and North 

 Cephaelis ipecacuanha, AND FLOWEK. America, again, similar means for resisting 



