EXPERIMENTS AND PRACTICAL WORK 33 



grow partly or entirely above ground, on six plants, 

 e.g. screw pine, mangrove, orchid, sugar cane. 



Expt. 14. Necessity for Roots. Cut the roots off a 

 weed ; plant it in the soil ; support it by a stake. Note 

 whether it grows or not. 



Expt. 15. Root-hairs. Grow some radish seedlings 

 on a piece of flannel and observe the tiny root-hairs. 



Expt. 16. Tuberous Roots and Tubers. Examine 

 the tuberous root of the cassava and compare it with 

 the tuber of a yam; put both aside in a moist place, 

 and observe that the latter readily develops shoots 

 from its " eyes ". 



STEMS AND SHOOTS I 



(See Tropical Readers, Book I, pp. 78-82.) 



Expt. 17. Food Solution travels up Stem from 

 Roots. Cut through the stem of a plant growing 

 vigorously, about 6 in. from the ground, and note the 

 " bleeding " due to the escape of food in solution going 

 up the stem from the roots. Do not confuse with 

 gummy matter given off by plants in order to heal 

 wounds. 



Expt. 18. Food Solution travels up through Woody 

 Portion of Stem. Put a branch (e.g. of a rose tree) 

 with leaves to stand in water coloured with red ink. 

 Expose in the sunlight for three or four hours. Observe 

 that the red ink has travelled up into the leaves, and, 

 by cutting across the stem and also peeling down a 

 piece of the bark, note that it has passed through the 

 woody portion of the stem only; the pith, cambium 

 layer, and bark will not have been reddened. 



Expt. 19. Underground Stems. Collect and make 



drawings of rhizomes of the ginger and iris; tubers of 

 ( C 282 ) 3 



