EXPERIMENTS IN CROSSING A WILD PEA FROM 



PALESTINE WITH COMMERCIAL PEAS, WITH 



THE OBJECT OF TRACING ANY SPECIFIC 



IDENTITY BETWEEN THIS WILD 



PEA AND PEAS OF COMMERCE. 



BY ARTHUR W. BUTTON, F.L.S., V.M.H. 



When I was travelling in Palestine in the spring of 1904 I noticed growing wild 

 amongst the vines, a small-podded Pea which appeared to differ from any I had 

 seen before. The pods on the plant were already ripening and I could not, there- 

 fore, see the colour of the blooms, but in the absence of any purple colour in the 

 axils (perhaps due to the advanced stage of growth) I hoped that the plant might 

 prove to be a white-flowering type, and, as such, an original form of Pisum sativum, 

 and thus also a possible parent of the garden Peas of the present day. 



It is generally agreed that all commercial Peas belong to one of two species, 

 either Pisum sativum or Pisum arvense, although some authorities consider Pisum 

 arvense to be a sub-species of Pisum sativum or vice versa. Pisum sativum includes 

 all those varieties of Peas grown by horticulturists, the seeds of which are used 

 for the table in a green state as " petits pois " (Pois a ecosser). These culinary Peas 

 have white flowers, with green, yellow or white seeds, either wrinkled or round in 

 form. On the other hand, all the varieties of field Peas (Pois gris or Pois dfourrage), 

 the produce of which is harvested in a dry state as corn, may be said to belong to 

 the species Pisum arvense, and in every case the varieties of this type have coloured 

 flowers (generally bicoloured) and distinct coloured markings in the axils, whilst 

 the seeds are invariably grey or brown and generally mottled. The only exception 

 to this general rule is that certain Peas belonging to the species Pisum arvense are 

 cultivated in gardens for culinary use, although these varieties are not grown to 

 produce " green peas " i.e., " petits pois," but to supply fleshy pods which are 

 sent to table whole. This class of Peas is known under the name of " Pois mange- 

 tout " or " Pois sans parchemin " ; the pods are of very delicate flavour and it is 

 for that reason they are grown, and not for the sake of the seeds which are always 

 very immature when the pods are ready for gathering. 



It is worthy of remark that the seeds of Peas belonging to the species Pisum 

 arvense, when eaten raw in a young and green state, leave a bitter taste in the 

 mouth ; whereas the seeds of every variety of Pisum sativum eaten under similar 

 conditions are relatively sweet to the taste. 



The outstanding features by which so-called varieties of Pisum arvense may be 

 readily distinguished from those of the so-called Pisum sativum are that the former 

 invariably have coloured flowers and colour in the axils, while the latter have 

 white flowers and there is an entire absence of colour in the axils. 



