I04 INTRODUCTION 



gall-wasps. According to Kerner ('Nat. Hist. PI.,' Eng. Ed. i, II, pp. 159-62), 

 there are two forms of fig-tree that is commonly planted in South Europe, i. e. that 

 of which the urn-shaped inflorescences contain female flowers only, and that pos- 

 sessing urns beset at the opening with male flowers and deeper down with gall- 

 flowers. The former is named Ficus, the latter Caprificus'. 



As the name itself indicates, the female flowers modified to form gall-flowers 

 do not produce fruits, but galls, which are due to a small wasp belonging to the 

 group Chalcidiidae (Blastophaga grossorum (rraz). = Cynips PsenesZ.). The females 

 of this wasp creep through the mouth of the urn into the interior of the inflorescence, 

 and each lays an egg near the nucellus of the ovule, sinking the ovipositor perpendi- 

 cularly into the style-canal of a flower. From the egg a white apodal larva develops, 

 which feeds upon the surrounding tissue, and consequently grows rapidly, soon 

 filling the ovary, while the ovule is destroyed. The ovary therefore becomes a gall. 

 Pupation next takes place, and finally the small perfect insect emerges by an aperture 

 that it has bitten in the gall, which has so far served as its abode. The males escape 

 first and fertilize the females, which are still in the galls. These subsequently escape, 

 and after a short stay in the urn make their way to the exterior. While creeping out, 

 they come into contact with the male flowers near the aperture, thoroughly dusting 

 themselves with pollen. After reaching the exterior they run (flight is rare) to 

 younger inflorescences, make their way into them, pollinate the stigmas of normal 

 long-styled female flowers, and lay their eggs in the short-styled gall-flowers. There 

 is therefore a division of labour between these two forms of female flower : the 

 stigmas of both are pollinated, and in both the wasps endeavour tO lay eggs. Into 

 the short-styled gall-flowers the eggs are thrust sufficiently deep, so that galls are 

 developed while there is no formation of fruit. In the normal female flowers the 

 style is so long that the eggs cannot be placed in the cavity of the ovary; hence 

 no galls are formed, but seeds capable of germination are produced. 



Kerner adds that in lower Italy, and elsewhere in South Europe where the 

 culture of figs has been practised on a large scale from very early times, Ficus trees, 

 i. e. plants in which the urns only contain seed-producing flowers, are for the most 

 part planted in gardens because they yield the best and most juicy figs. The fig- 

 trees of which the urns only enclose gall-flowers and male flowers, i. e. the so-called 

 Caprificus, are not planted, because most of their figs soon shrivel and fall oS'. 

 Only individual plants of Caprificus are cultivated here and there for the purpose of 

 hanging their urns on the branches of the Ficus. This is called Caprificalion, 

 and it is a prevalent opinion that when the wasps escape from the urns of the 

 Caprificus and wander into the urns of the Ficus, the figs of the latter are improved. 

 This opinion, although widespread among gardeners and agriculturists, is incorrect. 

 For, Kerner continues, the figs of the Ficus become sweet without the aid of the 

 wasps. As a matter of fact, excellent figs are produced from Ficus-urns which are 

 not visited by wasps, and in the fruits of which no seeds capable of germination have 

 been developed, and enormous quantities of the figs of commerce are produced quite 

 independently of caprificalion. It would appear, therefore, that this custom has been 

 handed down as a tradition from very ancient times — times when gardeners were 



' [Cf. Laubach, ' Die Herkunft, Domestication nnd Verbreitung des gewohnlichen Feigenbanms, 

 Ficus Carica L. Abh. Ges. Wiss., Getting., xviii, 1882. — Ed.] 



