GENERAL MOEPHOLOGY OF THE PLANT 21 



titbercular, and each enlargement is called a tnhcrcule. Such a 

 root occurs in various terrestrial Orchids, the Jalap plant, &c. 

 These tuberoules should not be confounded with tubers, which 

 are subterranean modifications of the stem. The presence 

 of buds on the latter at once distinguishes them. Inmany Orchids 

 (as, for instance, Orchis maculata) the tubercules are divided at 

 their extremities, so that the whole somewhat resembles the 

 human hand (Jig. 27) ; they are then said to be palmated, and 

 the root is also thus termed. When a number of tubercules 



Fig. 23. 



Fig. 2-t. 



Fig. 25. 



Fig. 2'i. Fusiform root of tlie common 



Eadisli {Raphamis saiicus ). 



Fig, 24. Napiform root of the Tur- 

 nip (Brassica Rapa). Fig. 25. 



Conical root of the Can-ot {Daucus 

 Carota), 



arise from a common point, as in the Dahlia (fig. 28), and 

 Bird's-nest Orchis (Neottia Nidus-avis), the root is said to be 

 fasciculated or tufted. 



When the branches of a root are expanded only at certain 

 points, other terms are applied. Thus when the branches are 

 enlarged irregularly towards the ends, as in the common Drop- 

 wort, the root is nodulose (fig. 29) ; when the branches have 

 alternate contractions and expansions, so as to present a beaded 

 appearance, as in Pelargonium triste, the root is moniliform, 

 nechlace-skaped, or headed (fig. 31) ; and when the root has a 



