ORGANS OF NUTRITION. 



129 



and arranged like a piece of coral {fig. 241), as in Corallorrhiza 

 innata. 



Tuberculated Root. — When some of the divisions of a root 

 become enlarged so as to form more or less rounded or egg- 

 shaped expansions {fig. 242), the root is said to be tuberculated, 

 and each enlargement is called a tubercle. Such a root occurs 

 in various terrestrial Orchids, the Jalap plant, &c. These tuber- 

 cles must not be confounded with tubers, which have been 

 already described as subteiTanean modifications of the stem. 

 The presence of eyes or buds on the latter, at once distinguishes 

 them. In many Orchids, as for instance the Orchis maculata, the 

 tubercles are divided at their ends, so that the whole resembles 

 the human hand {fig. 243), they are then said to be palmated, 

 and the root is also thus termed. 



Fig. 245. 



Fig. 244. 



Ftg, 244. Fasciculated roots of the Dahlia Fig. 245. Nodulose root of 



the cominou Dropwort {Spiraea Filipendula). 



Fasciculated, Clustered, or Tvfted Root. — These names are 

 applied inditferently to a root which consists of a number of 

 tubercles or fleshy branches arising from a common point {fig. 

 244), as in Asphodelus luieus ; the Dahlia ; Bird's-nest Orchis 

 {Neottia Nidus-avis), &c. 



Nodulose, Anmdated, and Momliform or Necklace-shaped Roots. 

 — These terms are apphed to roots which are expanded only at 



