WILD RADISH : JOINTED CHARLOCK 387 



The siliques, which are from i to 3 inches long, have 

 long slender beaks and are constricted above and below each 

 seed (4, Fig. 123) ; they are indehiscent, but separate at the 

 'joints' into barrel-shaped pieces, each containing a single 

 seed. 



The seeds are oval and reddish-brown in colour. 



The whole plant somewhat resembles ordinary Charlock, but 

 may be distinguished from the latter by its erect sepals, usually 

 veined petals, and smooth ' jointed ' siliques. 



Ex. 191. — Examine seeds of cabbage, swede and turnip in bulk, and indi- 

 vidually with a lens. Compare them with seeds of black mustard and 

 charlock. Taste all of them separately in the above order and note any 

 differences in flavour. 



Ex. 192. — Grow seedlings of cabbage, swede turnip, black mustard, white 

 mustard, and charlock. Note the shape of the cotyledons and first leaves of 

 each. 



Ex. 193.— Compare the external appearance of a full grown swede with that 

 of a white turnip. 



Ex. 194. — Carefully examine and describe the leaves, flowers and fruits of 

 the crucifers mentioned in detail in the text, and draw up a table of differ- 

 ences, paying special attention to the calyx, the colour and form of the 

 corolla, and the form of the siliques. 



Ex. 196. — Watch the growth of the fleshy 'root' of a turnip or swede. 

 Find out which part is hypocotyl and which true root. Make marks with 

 Indian ink, J of an inch apart, on the hypocotyl of young seedlings, and 

 note their position from day to day. 



Ex. 196. — Make careful observation on the development of a kohl-rabi 

 plant from the young seedling stage up to the time when the stem is 2 

 inches thick. Find out whether the part of the stem above or below the 

 cotyledons thickens most. 



Ex. 197. — Growbrussels sprouts, savoys, broccoli, and thousand-headed kail 

 side by side and watch their development : make notes of the differences in 

 length of stem and the development of the buds in the axils of the leaves 

 upon it, in each kind of plant. 



Ex. 198. — Examine the various forms of cabbage when the inflorescences 

 are well developed and their flowers open. 



Are the flowers of the different forms alike in all respects ? 



Ex. 199. — Compare and contrast longitudinal and transverse sections of a 

 turnip, a carrot and a mangel respectively. 



