FLOWERS 391 



for example, need to have other varieties planted near them, 

 if they are to prosper. Some plants need not only to have 

 other varieties planted near, but they also require the pres- 

 ence of special insects. 



One of the most striking examples of this is the Smyrna 

 fig. For many years attempts were made to introduce 

 this fig into California. The trees grew but the fruit did 

 not mature. It was then observed that in the regions where 

 this fig was successfully grown a species of wild fig was 

 abundant and that the natives were accustomed to hang 

 branches of the wild fig in the Smyrna fig trees at the time 

 they were in flower. These wild fig trees were brought to 

 California and grown near the Smyrna fig trees, but still 

 figs did not mature. Upon further examination it was 

 observed that at the time of flowering a small insect issued 

 from the wild figs and visited the flowers of the Smyrna figs. 

 This insect was brought to California and now it is possible 

 to grow figs. The flower of the Smyrna fig has no stamen and 

 it is necessary for the wild fig to furnish the pollen which 

 is only successfully carried to the stigmas of the edible fig 

 by the small fig-fertilizing insect. 



A somewhat similar case is that of the yucca found in 

 the dry region of southwestern United States. This flower 

 can be fertilized only by the aid of a small moth which flies 

 about at night from flower to flower. It enters the flower, 

 descends to the bottom, stings one of the ovaries, deposits 

 an egg, then ascends and crowds some pollen on the stigma. 

 The grub, when it hatches from the egg, feeds on the seeds 

 in the ovary, but as there are many seeds in the flower 

 which have been fertilized and the grub eats only a few of 

 these, the moth has made it possible for the yucca to pro- 

 duce seeds sufficient for its continued propagation, which 



