256 LUTHER BURBANK 



One of the most promising Australian species 

 is known as Passiflora edulis. It produces a 

 much larger quantity of fruit than the Maypop, 

 but is less hardy than that plant. Several of the 

 South American species are too tender to be 

 grown even in California. One of these, known 

 as Passiflora quadrangularis, bears a fruit about 

 the form and size of a small watermelon, yellow- 

 ish green in color, with an attractive edible pulp. 

 I have cultivated this species, but it has not 

 entered to any important extent into my experi- 

 ments, because of its extreme tenderness. 



The fruit of the species with which I have 

 chiefly worked (P. edulis) is usually about the 

 size of a hen's egg. 



The usual color is orange-yellow, but some 

 varieties have a purplish tinge, and a purple 

 pulp. Some of the species of the Southern 

 Hemisphere are recognized as producing valu- 

 able fruit, particularly for combination with 

 other fruits having a pleasant and unique flavor. 

 But the fruit of the Maypop has seldom been 

 considered worth picking. 



Experiments with the passion flowers began 

 about 1895. It was not difficult to grow the 

 plant from seeds received from different regions. 

 It is only essential to keep the ground warm and 

 moist. There is an astonishing difference in the 



