52 



HUTCHINSON'S POPULAR BOTANY 



Professor Kerner relates some curious facts to illustrate the protective 

 purposes of the milky juices of plants. These protective juices are not, as 

 in the case of the acid juices already referred to, required to keep off 

 birds and mammals, but to shield the plants, and particularly the floral 

 organs of plants, from the depredations of ants and other insects. Kerner' s 

 observations, recorded in his Flmvers and their Unbidden Guests, were confined 



to two species of the 

 Lettuce family Lactuca 

 angustana and the 

 Garden Lettuce (L. 

 saliva) ; and he thus 

 describes the effects of 

 the flow of juice on some 

 ants whose little hooked 

 \i ^F; feet had cut through 

 the epidermis of the 

 plants in certain places, 

 and thus induced the 

 flow: "Not only the 

 feet of the ants, but 

 the hinder parts of 

 their bodies, were soon 

 bedrabbled with the 

 white fluid ; and if the 

 ants, as was frequently 

 the case, bit into the 

 tissue of the epiderm in 

 self-defence, their 

 organs of mastication 

 also at once became 

 coated over with the 

 milky juice. By this 

 the ants were much im- 

 peded in their move- 

 ments, and in order to 



The seed-capsules of the Opium-Poppy (Papaver somniferum). One to the right rid themselves of the 

 is cut open to show the divisions of the interior. The others show the open doors 



Photo 6y] 



Fm. 77. POPPY- HEADS. 



the roof which regulate the dispersal of the seeds. 



annoyance to which they 

 were subject, drew their 



feet through their mouths, and tried also to clear the hinder part of their 

 body from the juice with which it was smeared. The movements, however, 

 which accompanied these efforts simply resulted in the production of new 

 fissures in the epiderm, and fresh discharges of milky juice, so that the 

 position of the ants became each moment worse and worse. Many of them 

 now tried to escape by getting, as best they might, to the edge of the 



