LUTHER BURBANK 



quite subject to insects and disease. The hybrid 

 forms are much more resistant. There is also a 

 greater power on the part of the new plants to 

 stand sunshine. The old tigridias sometimes with- 

 ered under the influence of the sun. This might 

 not at first thought be expected of a tropical plant, 

 but it should be recalled that the growth of vegeta- 

 tion in tropical regions is so luxuriant that low- 

 growing plants of this order are not usually sub- 

 ject to the direct rays of the sun throughout the 

 day. 



It goes without saying that the bulbs of the 

 new tiger plants were improved in proportion to 

 the stalks and flowers. The bulbs of the tiger 

 plant are elongated and tunicated, and multiply 

 by division somewhat after the manner of the 

 hyacinths, tulips, and the allied races in general. 



The bulbs of the new hybrid tigridias were 

 doubled in bulk, and in some cases quadrupled, as 

 contrasted with the parent forms. Like the some- 

 what similar bulbs of the gladiolus, they may best 

 be kept in the ground over winter here in Califor- 

 nia, instead of being taken up and stored as is 

 necessary in colder climates. 



The development of the bulbs of the tigridias 

 has not been at all a matter of accident. At all 

 stages of the experiment in hybridizing and selec- 

 tion, I have paid the most careful attention to the 



[86] 



