220 VEGETABLE ORGANOGRAPHY. 



such are those of the Hyacinth and jnost of the Lili- 

 acese. 3d, It often happens that the same neck gives 

 origin, both to cyUndrical fibres such as I have described, 

 and to some fibres swollen up into round or oblong tu- 

 bercules, simple, or slightly branched, full of fecula or 

 mucilage, which seem to be reservoirs of nutriment in- 

 termixed with absorbing fibres: such are the fascicu- 

 lated roots of most of the European Orchideje, the 

 Asphodels, &c. 4th, All the fibres which spring from 

 the neck may present swellings more or less evident, 

 and thus form bundles or bunches of oblong tubercules ; 

 such are those of the Dahlia, of several kinds of Ranun- 

 culus, &c. These four classes of compound roots are so 

 nearly connected, that intermediate examples are found 

 between all of them. 



We designate collectively vmder the name of Tube- 

 rous Roots, all those which have swellings in any part 

 of their length ; the preceding enumeration has already 

 proved that this phenomenon can exist in very different 

 organizations. We may also add to these examples, 

 that of lateral tubercules, which are developed here and 

 there along fibrous roots with a single base ; as for ex- 

 ample in Ornithopus perpusillus, and several other her- 

 baceous Papillionacese, and that of the swellings or 

 nodosities which are observed here and there along the 

 fibres of several fibrous roots, as in Taxodium. But 

 these curious swelhngs seem so slightly connected with 

 the generality of the structure, that they can be but 

 little considered as classes of roots. 



It must also be observed, that several tubercules which 

 seem most evidently to arise from the root, are developed 

 in reality along the lower branches of the stem buried 

 under ground. Dunal was the first who proved that this 

 took place in the Potato, and Turpin has confirmed it. 

 This kind of tubercule will occupy our attention elsewhere. 



