12 



DICOTYLEDONS 



pour water on them, you will see that the water is taken ;o the 

 stem and runs down to the root. 



3. The Root system of the Mustard plant, instead of spread- 

 ing to a distance in all directions like that of, for instance, the 

 Mango tree, forms a distinct tap-root Avith a few thin side-roots 

 only. It is for this reason that in the Mustard plant the leaves 

 carry the water to the centre of the root system. 



4. The Flowers of the Mustard plant are bright yellow and 

 have four sepals and four petals. The 

 latter are stalked and grow inside, but 

 alternate with the sepals. There are six 

 stamens, two with short filaments, and four 

 (inside) with longer ones 

 (tig. 7). The centre of the 

 flower is formed by an 

 ovary with a short style. 

 If cut across (see diagram, 

 fig. 8), it can be seen that 

 it is made of two carpels, 



Fig. 7. — Flower of Mustard 

 (Brassica juncea). One sepal 

 and two petals are removed. 

 (3 times natural size ) 



the edges of which each Fig. 8— Diagram of 



1 i? 1 „ a Crucifer flower. 



bear a row ot ovules. 



The bright colour of the fiowers, which open at the same time 

 and in large numbers, attracts the passing 

 insects to look for the honey which is there 

 at the base of the stamens. The insects pay 

 for the kindness of the flower in providing 

 them such a nice drink by spilling pollen 

 on the stigma of the style and so fertilising 

 the seeds. 



5. The Fruit is a long erect pod formed 

 of two dry carpels which split upwards and 

 outwards from the base showing the seeds 

 growing on a central frame (fig. 9). Such a 

 pod is called a sili(|ue. 



Fig. 9.— Siliijuo of 



the Mustard plant. 



A'. Carjjels. W. Central 



fraiiio. .S. Soeds. 



(Natural size.) 



Other Crucifers. 



The family to whicli the Mustard plant belongs, contains a 



