CONTENTS OF CELLS AND VESSELS. 



I8 7 



are called " raphides."* You would find crystals of 



another shape in 

 stalks of rhubarb. 



the 



Now we will pick a 

 dandelion, and notice its 

 milky juice. It is con- 

 tained in vessels, long 

 tubes or ducts, which 

 spread thickly both in 

 root and flower stalk. Fig . , 66 ._ Crystals and Raphides . 

 Common sun's purge also 



has a quantity of milky juice which is contained in 

 cells, and is white in colour as in the dandelion. But 

 do you know the greater celandine ? t It is a plant 

 with little clusters of yellow flowers, each of 

 four petals, and its seed vessel is a pod ; it grows in 

 waste places, thickets, and often about old houses. 

 Its abundant milky juice is yellow. 



In some plants this kind of milky juice is very 

 valuable. Opium for instance is the milky juice 

 which is found in the capsules of a certain kind 

 of poppy, J and the milky juice of a foreign 

 plant, of the same natural order as our common 



* From the Greek " raphis" a needle. 



t Not the buttercup celandine (Ficaria verna), but quite a different 

 plant, the Chelidonium majus. 



| Papaver somnifertttn. 

 Siphonia elastica. 



