FOEMS OF EOOTS. 



41 



and when cut in pieces they give rise to buds and new plants. This 

 occurs in the Ipecacuan plant. 



Fig. 100. 



Ilg. 101. 



Pig. 102. Kg. 103. 



In some Dicotyledonous roots, as in the Oar- 

 rot and Beet, there is a circle of fibro-vascular 

 bundles, which are separated by medullary rays. 

 In the turnip these bundles are immediately 

 under the rind, and in the inner portion of the 

 root the bundles are separated from each other by 

 a great development of cellular tissue. In these 

 peculiar thickened roots it is often difficult to 

 determine their structure. They have more of 

 the aspect of stems, and have been called Hypo- 

 cotyledonary stems. The structure in several 

 fleshy Dicotyledonous roots resembles that of 

 Monocotyledons. 



In Dicotyledonous plants the root, in its early state, or the radicle, 

 as it is then called, is a prolongation of the stem, and elongates 

 ■directly by its extremity. It then continues to grow in a simple or 

 branched state (fig. 98). From this mode of root development, 

 these plants have been called Exorhiml (e^ta, outwards, and j/^a, a 



Fig. 100. Fasciculated root of Asphodelus luteus. Fig.' 101. Tubercular roots or stem- 

 tubers of Orchis. Several of the radical fibres retain their cylindrical form, whUe two are 

 tubercules containing starchy matter. Fig. 102. Nodulose root of Spiraaa Filipendula. 

 Fig. 103. Moniliform root of Pelargonium triste. Fig. 104. Ipecacuan (Cepliams Ipeca- 

 cuanha), with an anm\lated root. 



Fig. 104. . 



