666 Mutations 



leaved ^' strawberry has already been referred 

 to. It originated from the ordinary type in 

 Norway and at Paris. The walnut likewise, has 

 its monophyllous variety. It was mentioned 

 for the first time as a cultivated tree about 1864, 

 but its origin is unknown. A similar variety of 

 the walnut, with '^ one-bladed " leaves but of 

 varying shapes, was found wild in a forest near 

 Dieppe in France some years ago, and appeared 

 to be due to a sudden mutation. 



Something more is known concerning the 

 ** one-bladed " ashes, varieties of which are 

 often seen in our parks and gardens. The com- 

 mon form has broad and deeply serrate leaves, 

 which are far more rounded than the leaflets of 

 the ordinary ash. The majority of the leaves 

 are simple, but some produce one or two smaller 

 leaflets at their base, closely corresponding in 

 this respect to the variations of the '' one- 

 bladed " bastard-acacia, and evidently indicat- 

 ing the same latent and atavistic character. In 

 some instances this analogy goes still further, 

 and incompletely pinnate leaves are produced 

 with two or more pairs of leaflets. Besides 

 this variable type another has been described 

 by Willdenow. It has single leaves exclusive- 

 ly, never producing smaller lateral leaflets, 

 and it is said to be absolutely constant 

 from seed, while the more variable types 



