66 



THE VEGETATIVE FUNCTIONS OE PLANTS 



Fig. so. — Photomicrograph of a, portion of the system of veins in a 

 leaf of the rubber-plant {Ficus elastica) . Enlarged about six times from 

 a portion of Fig. 49. 



Fig. SI- — The castor-oil plant {Ricinus communis). Portion of cross- 

 section of young stem, co, Cortex; p, pith or medulla; e, epidermis; ph, 

 phloem; ca, cambium; x, xylem. The last three elements compose the- 

 fibro-vascular bundle, the cambium being continuous from bundle to 

 bundle; the portion between the bundles is called interfascicular cambium. 



