Vegetable and Animal 



amongst them seem to be seldom or never poisoned* 

 So that there must be some educational influence at 

 work ; practical botanical knowledge is somehow ac- 

 quired by the growing calf. 



One very curious instance of the close relation of 

 plants and insects is found in certain fungi. There are 

 no less than 708 species of fungi which grow on the 

 droppings of herbivorous animals, 45 species on that of 

 carnivorae, and four on that of reptiles. 6 The common- 

 est (Ascobolus) forms the little brown-red saucers which 

 cover such surfaces. The tiny transparent spores are 

 squeezed or darted out of the fungus and fall on the 

 grass leaves, to which they at once adhere and become 

 cemented. They are eaten with the grass by cattle, and 

 pass uninjured through its complex digestive system. 



The adaptations of special insects to the times and 

 seasons of plant life are very remarkable. The spruce 

 gall insect, e.g., forms those small, withered-looking 

 galls which are exactly like diseased first year's cones, 

 and which are very common on spruce twigs. There 

 are five forms of the insect. The " foundress " wingless 

 females produce the galls. Their larvae live in them 

 but eventually get wings, and as " colonisers " fly to 

 the larch or pine, where they winter in crevices of the 

 bark ; their children live on the larch leaves or pine 

 needles, and lay eggs which become male and female 

 winged insects. The females return to the spruce and 

 their progeny are " foundresses." 7 The changes are 

 in reality even more complex than these. 



This insect continues on the spruce, but also has the 

 chance of using two other trees. 



It is, however, when one tries to unravel the manifold 

 relations of a green-fly to the plant and animal world 

 that one begins to realise something of the way in which 

 Nature works. The aphis or green-fly of the hawthorn 



200 



