ROOT AND SUBTERRANEAN STEM. 



75 



but are found also in some Exogens, — the Sweet Potato, 



Dahlia, Peony, etc. They 

 are Fibrous (thread-like) 

 in the Grasses (Figs. 6, 

 57) ; Tuberous, or tuber- 

 like, in the Yam (Fig. 

 89) and Sweet Potato. 



145, Tuberous roots are 



distinguishable from the true 

 tuber in being without buds, 

 or Eyes ; they develop leaves 

 and stems only from the ex- 

 tremity. (Compare Pigs. 

 89 and 95.) They are 



Coralline, like coral, in the 

 Coral-root Orchid ; 



Fasciculate, bundled, in the 

 Asphodel (Fig. 56) ; 



Filipendulous, hanging sep- 

 arately at the end of a long 

 Fio. 89.— Kt., St., with IvB. and fls., of Yam fibre, in the Dropwort ; 

 (Dwscorea aativa) of West Indies and Southern JMonilifoTTn, necklace-like, 



States. Lts. do not show the ribs plainly enough. ];]je a string of beads, in the 



Pelargonium and Ipecac (Fig. 

 90). 



146. Air-Plants, or Epiphytes 

 (Gr. epi, upon, phyton, plant), do 

 not grow in the ground, but rest 

 upon other plants, and draw their 

 food from the air. They are 

 chiefly of the Orchis and Pine- 

 Apple Orders, growing in warm, 

 moist climates. The Magnolia 

 Orchis ( F.pidendron) and Spanish, 

 or Florida, Moss [Tillandsia) are 

 examples. In these the roots serve 

 the same purpose as in other 

 plants, — support and absorption. 



147. Adventitious, or Sec- 

 ondary Roots will spring from 

 any part of the stem if it be 

 favorably placed. We see this 

 in cuttings and slips. The In- 

 dian Corn and Sugar-Cane send 

 out secondary roots from several 

 joints near the ground ; the Mangrove of our Southern States sends 

 them out in such size and abundance that it gets its generic name-^ 

 Rhizophora, Koot-bearer— from them. The Banyan (Fig. 91) sends 

 them down from its wide branches, making a miniature forest; one 



Fig. 90. — Rt., St., and Ivs. of Ipecac {Ch-ph- 

 aelis IpecoGimnha) of Brazil. 



