68 



STRUCTURAL BOTANY. 



ical. To all these forms the general name tap-root is applied. 

 The ramous is the woody tap-root of most trees and shrubs, 

 where the main-root branches extensively, and is finally dissolved 

 and lost in multiplied ramifications. 



203. Tuberous tap-roots. In herbaceous plants the tap- 

 root often becomes thick and fleshy, with comparatively few 

 branches. This tendency is peculiarly marked in biennials (41), 

 where the root serves as a reservoir of the superabundant food 

 which the plant accumulates during its first year's growth, and 

 keeps in store against the exhausting process of fruit-bearing in 

 its second year. Such is the Fusiform (spindle-shaped) root 

 thick, succulent, tapering downward, and also for a short space 

 upward. Beet, Radish, and Ginseng are examples. The Con- 

 ical root tapers all the way from the collum downward (Carrot). 

 The Napiform (turnip-shaped) swells out in its upper part so 

 that its breadth equals or exceeds its length, as in Erigenia (235) 

 and Turnip (239). 



237 



240 



!C7, Maple au axial, ruinous root. 238. Parsnip a fusiform root. 239, Turnip a napiform root. 240 

 Corallorhiza a coralline root. 



204. The forms of ihaxial roots are fibrous, fibre-tuber 

 ous, tubercular, coralline, nodulous, and moniliform. The fibrous 

 root consists of numerous thread-like divisions, sent off directly 

 from the base of the stem, with no main or tap root. Such are 

 the roots of most Grasses, which multiply their fibres excessively 

 in light sandy soils. Fibro-tuberous roots (or fasciculate) are 



