76 THE BOOK OF NATURE STUDY 



the ovary, together with, in some cases, other parts of the flower. 

 In most dry fruits which contain a number of seeds the fruit 

 opens or splits in pieces to allow of their separate dispersal. 

 But when a dry fruit contains only one seed this is unnecessary 

 and such fruits do not as a rule open, but are dispersed entire, 

 the wall of the fruit serving to protect the seed within. Succulent 

 fruits, whether one- or many-seeded, do not usually open, but 

 their seeds are separated and scattered in a different way. 



Some plants show little or no special provision for the scatter- 

 ing of their seeds. The large seeds of the Pea, for instance, simply 

 become detached and fall from the pod when it opens, and the 

 same may be said of the Charlock and the Plantain, where the 

 seeds are smaller. Often, however, the fruits, borne on long 

 stalks or on the slender branches, sway in the wind, and when they 

 open the small seeds will be shaken out and fall at some little 

 distance from the parent. The Poppy (Vol. IV. p. 21) and the 

 Red Campion are good examples of such a simple and little 

 specialised method of seed-dispersal. 



Another group of fruits eject their seeds more or less forcibly 

 when they open, so that they are cast to some distance from the 

 plant. This happens when the pod of the Bird's-Foot Trefoil 

 splits open. The two halves coil spirally on the sudden opening, 

 and the seeds are propelled away. The noise of the similar sudden 

 opening of the pods of the Whin or Broom is familiar to every one 

 who has stood among these plants on a warm summer day when 

 their fruits are ripe. Other plants among those described which 

 show arrangements of this kind to disperse their seed are the 

 Herb-Robert (Vol.111, p. 198, Fig. 91) and the Wild Pansy (Vol. III. 

 p. 128, Fig. 65). 



Many plants are assisted in the spread of their fruits or seeds 

 by the wind. This may happen even when these parts show no 

 special modifications, but is much more efficient in seeds or fruits 

 adapted for the purpose. The extreme lightness of the seeds of 

 the Orchid fit them for wind-dispersal, but the minute seed can 

 carry no store of reserve food material, and take a long time to 

 produce a mature plant. In the Ash (Vol. IV. p. 55) and Sycamore 

 (Vol. IV. p. 60, Fig. 16) the fruits are winged, and so offer a large 

 surface to the wind. When they fall from the tree they will 



