POLLINATION OF FIG 373 



rarely three, in the course of a year. The wasp seems to go 

 through three generations, though this is not quite certain. 



From the earhest times it has been known that the 

 presence of the caprifig is necessary for the production of a 

 crop on the fig. " Caprification " is an established feature 

 of fig cultivation in many places. The peasant grows 

 caprifigs among his fig trees, or grafts shoots on the figs, or 

 even hangs branches in the bearing trees. When the 

 Smyrna fig was planted in California it was found necessary 

 to introduce the caprifig, v/ith the Blastophaga, before a 

 crop could be obtained. In the north of Italy caprification 

 is not practised ; the varieties of fig grown there are 

 parthenocarpic, and produce swollen fruit without fertilisa- 

 tion. These do not keep well and cannot be dried ; the 

 dried figs of commerce always contain seed. 



The caprifig bears gall flowers and male flowers ; the 

 fig bears only female flowers, which in one generation are 

 sterile. We have here a unique case in which a monoecious 

 wild plant has been changed by selection (unconscious 

 doubtless, since it occurred in very early times) into a 

 dioecious cultivated form. The caprifig is essentially male, 

 the fig female. Only in cultivation can this condition be 

 maintained, for the seeds of the fig revert to the wild species ; 

 artificial propagation by cuttings and grafting is necessary 

 to carry on the cultivated fig. 



II. Ornithophilous Flowers 



This mode of pollination is of considerable importance in 

 some countries, e.g. in Patagonia, West Australia, South 

 Africa, and Brazil. The birds which are active are small 

 honeysuckers, sun-birds, and humming-birds, often not 

 bigger than moths. A recent paper by Werth (19 15) gives 

 an interesting account. In general, there is no such marked 

 difference between a bird flower and an insect flower as 

 between either and a wind flower. Many bird flowers are 

 also visited by insects. In both the colours are brilliant, 

 but in bird flowers reds and especially scarlets are frequent. 



