216 THE EVOLUTION OF OUR NATIVE FRUITS 



able, and the plant is probably not in cultivation out- 

 side 'of botanic gardens and experimental grounds 



There is a form of this Pacific plum which produces 

 attractive fruit, however. This is the so-called Sisson 

 plum, bearing the name of Mr. Sisson, of Strawberry 



Fig. 34. Pacific coast plum. (Primus subcordata.l Natural size. 



valley, near the base of Mt. Shasta, who has been 

 instrumental in bringing it to notice. This form is 

 known as Prunus subcordata var. Kelloggii (J. G. Lem- 

 mon, Pittonia, 1890, p. 67). The tree is a taller grower 

 than P. subcordata itself, the leaves less cordate, and 

 the fruit larger, yellow or red, soft and palatable. 

 Luther Burbank writes me that the twigs of yellow - 

 fruited plants are greenish yellow, and those of the 

 red -fruited plants are reddish brown. He also tells 

 me that seeds of the yellow fruits may produce red 



