MINOR CROPS. 327 



erect growth, the plant can be harvested more easily than the 

 cowpea, and for the same reason can be more readily ploughed 

 under as a green manure. 



THE FIELD PEA. 



Piper says : — " It is customary to distinguish agricultur- 

 ally between the garden pea {Pisum Jiortense) and the field or 

 Canada pea {Pisum arvense), but whatever characteristics are 

 used, there are all possible inter-grades in the long series of 

 cultivated varieties. In general the term field pea is restricted 

 to those having somewhat angled, brown to black or marbled or 

 speckled seeds and coloured flowers ; garden pea to those having 

 white flowers and round, yellow seeds. But several varieties 

 are used both for vegetables and for forage." 



In South Africa field peas are looked upon as winter rather 

 than summer annuals, since their growth during the hot months 

 is extremely poor. 



They are fairly resistant to drought.. Except in the winter 

 rainfall area, however, they must be grown under irrigation. 



Description. — -They are usually decumbent, pale green 

 and glaucous; the leaves are pinnate, with one to three pairs 

 of leaflets ; numerous tendrils ; having stout axillary preduncles 

 bearing each one to three flowers. Those seeds, having a very 

 angular form, owe their shape to a higher sugar content and 

 consequently greater shrinkage when drying. " The colour of 

 the seeds when of a single tint may be yellow, pea green, brown 

 or black. Yellow or green seeds may be marbled with brown 

 or speckled with blue, black or brown, or both marbled and 

 speckled. The embryos are yellow in yellow seeds and green 

 m green seeds." Numerous varieties are found. They are 

 best sown with oats, but will do well with rye. In general 

 they do well when used for the same purposes as those described 

 for the vetches. In mixtures a quantity of peas equal to that 

 of the cereal should be used. When grown for seed they must 

 be planted early enough to ensure the setting of pods before the 

 w^arm summer weather arrives. Unlike the vetches, when 

 grown for seed they are badly attacked by the pea weevil (Laria 

 pisorum or BrucJius pisorum) , which lays its eggs on the devel- 

 oping pod ; the larva hatches and burrows into the young seed 

 and remains for a considerable period in the mature seed. 



