6 THE BOOK OF NATURE STUDY 



After pollination the petals and stamens fall off, and the 

 ovary, still crowned by the stigmas and the withered 

 remains of the nectary, develops into the fruit. 

 This is a flattened oval body (Fig. 3) consisting of 

 two halves, in each of which is a single seed. 

 As the fruit ripens the two halves split apart 

 from below, but do not open to liberate the seeds. 

 They remain for a time attached to a slender 

 FIG. 3. Fruit cylindrical middle column, from which they ultim- 

 of the Cow- ately fall off and, being light and flat, may be 

 Parsnip. carried by the wind Qn each half of the fruit 



(After Bail- J . 



ion.) nve dark lines three on the outer face, two on 



the inner will be noticed. These are oil glands, 

 and are commonly present in the fruits of the Umbelliferae. 



THE POTATO (Solanum tuber osum, L.) 



The Potato plant is universally cultivated in temperate regions 

 for the sake of its tubers, which not only form one of our most 

 important vegetables, but are of economic importance as a source 

 of starch and in other ways. The plant is not a native of Europe, 

 but was introduced from South America in the sixteenth century. 

 It is still found wild in the Andes. Any of the very numerous 

 varieties will serve for study. Like other flowering plants, the 

 Potato is reproduced by seeds formed in the fruit, but this method 

 is not practically used nor was it probably the chief means of 

 reproduction in the natural state. In cultivation seedlings are 

 only raised for the purpose of obtaining new varieties. These 

 when obtained are multiplied and grown by means of the tubers ; 

 this is not only quicker and easier than growing the plants from 

 seed, but has the great advantage of transmitting unchanged the 

 characters of the particular variety. 



In ordinary cultivation the Potato is grown from the tuber, 

 which is planted in the spring or sometimes in the preceding 

 autumn. The tubers, the origin of which will be described below, 

 are the swollen ends of underground branches. The swollen 

 stem bears a number of small scale-leaves, which soon fall off 

 leaving curved scars. In the axil of each leaf is a bud, usuall) 



