THE STEM. . 21 



globe or head, from the under surface of which, many 

 fibres descend. 



The tulip, lily, snow- drop, crocus, and many other familiar garden 

 plants, are very good examples of this root; but bulbous roots are 

 divided into three sets, according to the peculiarity of their struc- 

 ture. When they are of one firm compact substance, as the crocus 

 and turnip, they are called solid bulbous roots (F. 26) ; if in plates 

 or scales, as with the lily, scaly bulbous roots (F. 18) ; and if they have 

 coats or layers one over another, as with the onion, (F. 23) they are 

 then termed coated bulbous roots. 



8. The species of root called tuberous consists of a 

 knot or tubercle, furnished with a number of small or 

 scattered fibres, or of a number of knobs or tubercles 

 united by the means of such fibres, and forming clusters. 



There are many plants with this order of root, but the potatoe, 

 earth-nut, peony, ladies-traces, white saxifrage, and sweet flag, are 

 examples so very common, that any other references would be 

 needless. (F. 30.) 



9. In many plants, the root is systematically divided 

 into two parts, the caudex or great root and the radicula 

 or rootlet. 



The caudex is the main root from whence the stem arises, and 

 from which the rootlets or fibres are given off; or to explain it more 

 practically if you take a tulip root, that part of it which forms a 

 solid bulb, is the caudex, and the threads which proceed from it, the 

 rootlets. The caudex is also intended to be represented by the 

 letter a, F. 26, and the rootlets, by the letters b b, in the same figure . 



1. The stem is that part of a plant arising from the 

 root, and maintaining the leaves and other necessary 

 appendages. 



