116 



COMPENDIUM OF GENERAL BOTANY. 



tissue generated from the interior, but tlie liistory of its growth and 

 development may differ very much in different cases. Behind the 

 root-ca^)-, as this organ is called, lies the true root-hody^ which is 

 especially adapted by the numerous root -hairs on the outer surface 



Fig, 63. — Longitudinal section of the root-tip of ErwpJiorwn vaginaium. 

 2, c, Root-cap; e, epidermis; >•, parenchyma; p, vascular system. (After Haberlandt.) 



to take up food-substances. The root-cap thei-efore covers the 

 cell-forminff vegetative area, which could not withstand the friction 

 caused by contact with the sharp-angled particles of earth. 



The root-cap may 1. develop from a formative tissue designed 

 for that purpose; examples: Triticuin rejjens («), Calla jxilustris 

 (^.) In type (a) there is a sharp distinction bet\veen the meristem 

 of the root and that of the root-cap ; in type {0) there is no such 

 distinction. 



2. These two types among monocotyledons are represented liy 

 two corresponding tyj)es among dicotyledons, but which differ es- 



