64 



BOTANY. 



canlome and phyllome. They present fewer variations 

 than any of the other generalized forms. The ordinary 

 (1) Subterranean roots of plants are typical. They differ 



PiO. 38. 



Fia. 



Fio. 38.— Diagrams of dichotomouE branoUng. A, normal dichotomy, in 

 whicli each branch is again dichotomously branched; B^ hellcoid dichotomy, in 

 which the right-hand branch, r, does not develop further, while the left-hand 

 one, I, is in every case again branched; C scorpioid dichotomy, in which the 

 branches are altematply further developed. 



Fig. 39. — Diagram of botryose monopodial branching. The numerals indicate 

 the "generations." 



but little from one another in whatever plants they may 

 be found. 



The other root-forms are: 



(2) Aerial roots, which project into the air, and often 

 have their epidermis peculiarly thickened, as in the epi- 

 phytic orchids. 



(3) Boots of Parasites, which are usually quite short, 



