INDEHISCENT AND DEHISCENT FRUITS 367 



Sometimes a whole inflorescence develops into a 

 single fruit (often called an " aggregate fruit "). In 

 the fig, for instance, the axis of the inflorescence is 

 concave, bearing the crowded flowers on its inner surface. 

 In fruit the axis (common receptacle of the flowers) 

 becomes succulent, the ovaries (" pips ") remaining 

 hard. In the pineapple the whole of the flowers of 

 the inflorescence (including perianth and stamens), 

 as well as the bases of the bracts, become succulent. 

 The hard tips of the bracts are exposed on the surface 

 of this " aggregate " fruit. 



Indehiscent and Dehiscent Fruits.— Sometimes the 

 change in form and appearance of the carpels in the 

 passage from flower to fruit is very slight, as in 

 the buttercup, rose, strawberry. In the buttercup, for 

 instance, the carpels, which are one-seeded, scarcely 

 grow at all, but their walls become dry and membranous, 

 changing in colour from green to brown. When ripe 

 they are easily detached from the receptacle and are 

 shaken off by the wind. The pericarp softens and 

 decays in damp soil, and when the seed inside germinates 

 the young plant pushes through its remains. This 

 is called an indehiscent fruit, because the pericarp does 

 not open when the seeds are ripe. A dry one-seeded 

 membranous walled fruit of this kind is called an 

 achene. It is a common type, not only in the butter- 

 cup family (Ranunculacese) , as in buttercup, anemone, 

 clematis, but also in the rose family (Rosaceae), where 

 it is found in cinquefoil {Potentilla), herb-bennet (Geum) 

 and others ; and it may, as we have seen, be associated 

 with a succulent receptacle (rose, strawberry) . Much 

 the same type of fruit is found in the great family 

 Compositse, in which the flowers are aggregated in close 

 heads (dandelion, thistle), and the outer ones are 



