THE ANGIOSPERM\E: ROOTS 



817 



Fig. 814. — Dendrobiiun sp. Aerial roots of an 

 epiphytic Orchid, covered with white velamen 

 tissue. 



Pic 815 —Vanda teres. Transverse section of an aerial 

 root showing broad zone of velamen and thickened 

 exodermis. 



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