92 



CASSELL'S POPULAR GARDENINa. 



THE LIFE-HISTOET OF PLANTS. 



Bt Db. Maxwell T. Masters, F.E.S. 



NVTRITION.-BOOTS AND ROOT-STOCKS. 



FROM -wliat has heen said in previous chapters, 

 it will he evident that the popular concep- 

 tion of a, root is -widely different from that enter- 

 tained by 

 the hotanist. 

 To the ordi- 

 nary obser- 

 ver any por- 

 tion of the 

 plant that is 

 beneath the 

 soil is a root. 

 But, quite ir- 

 respectively 

 of the acci- 

 dent of po- 

 sition, the 

 botanist re- 

 cognises the 

 root as a dis- 

 tinct organ 

 by its exter- 

 nal confor- 

 mation and 

 internal 

 structure, by 

 its mode of 

 growth, and 

 more ^spe- 

 cially by the 

 work that it 

 has to do. 

 There are, 

 however,cer- 

 tain organs 

 more or less 

 intermediate 

 between 

 roots and 

 stems, and to 

 some extent 

 having the 



properties of both, to which a few words may with 

 advantage be at this point devoted. 



Eoot-stocka. — Closely allied, indeed, both in 

 structure and in function to the bulbs, tubers, and 

 other underground developments of which mention 

 has ah'eady been made, are the "rhizomes" or 

 " root-stocks," or, as they are sometimes called, the 

 " stocks." It is impossible to draw any sharply- 

 defined line of definition between these and the pre- 



Pig. 36.— Subterranean Stem of Caxex, With shoota produced in snccession during four 

 years, and giving oif roots from tne under surface. 



ceding organs on the one hand, and roots taken in a 

 general sense on the other, nor in this place is it at 

 aU necessary to attempt to do so. They vary in 

 form in different plants, and serve as means to dis- ^ 

 criminate between different species, on which ac- 

 count alone they should be carefully noted by the 

 student, whUe as furnishing indications for appro- 

 priate modes 

 of cultiva^ 

 tion they are 

 of the high- 

 est import- 

 ance. Gene- 

 • rally, they 



are under- 

 ground 

 stems or 

 branches, 

 more or less 

 elongated 

 vertically or 

 horizontally, 

 or develop- 

 ments of the 

 caulicle (see 

 Vol. I., p. 

 87); usually 

 rather thick, 

 sometimes 

 slender; 

 branched, or 

 rarely un- 

 branched ; 

 having no 

 true leaves 

 underground 

 but merely 

 little mem- 

 b r a n u s 

 scales, which 

 represent 

 leaves in an 

 undeveloped 

 and func- 

 tionless con- 

 dition. They 

 give off true root-fibres, and therefore are often con- 

 founded with roots ; but, apart from other distinc- 

 tions of minute structure and mode of growth, it 

 may be pointed out that, as a rule, no true root pro- 

 duces leaves or even leaf-scales. The root-stocks 

 frequently produce a tuft of leaves at the upper end 

 or " crown," as may be seen in a Strawberry plant, 

 in the Carrot, or in the common Plantain [Flantago). 

 The gardener's term " parting the root " applies to 

 the subdivision of the crown of the rhizome. Ey 



