62 Plants and their Ways in South Africa 



across and the paths will show as small round dots. They show 

 plainly in Pumpkin stems as strong slender threads. These 

 threads are bundles of still smaller tubes or vessels, and so the 

 strands are known as vascular bundles. Break off a Violet 

 leaf; the vascular bundle may be drawn out from the broken 

 end. The petioles of Plantain or Wild Sago, which grows along 



P 



Fig. 69. — Leaf of Privet. E, epidermis of upper ; Ej, of under surface ; 

 C, cutic'e ; P, palisade cells ; V, vascular bundle enclosed in its sheath ; S, 

 stoma, G, guard cell ; G/, gland. (From Farmer's " Practical Introduction to 

 the Study of Botany".) 



sluits, show the vascular bundles nicely. They may be traced 

 to the veins of the leaves in which they end. They even pass 

 to all parts of the flower. In the Strawberry they may be easily 

 seen passing into each " seed " of the fruit. All parts of the 

 plant must be nourished. 



Ex. 26. From a woody stem bearing leaves (a willow is good for the 

 purpose), remove a ring of bark down to the wood. Place the lower end 

 in water over which a layer of oil has been poured; cover with a bell-jar. 

 The water will be used up and the leaves will transpire water vapour. 



Ex. 27. Carefully separate the bark from the wood at the lower end 

 of the stem; remove the wood and place the stem so that only the bark 

 is in the water. The leaves quickly wither. This shows that water is 

 carried up through the wood. 



