116 TEST CASES [ch. xi 



families, and have shown that even when fully fledged it is im- 

 possible to find any functional reason for their existence, and 

 equally impossible to show why one should be preferred to the 

 other, or to any (not commonly possible) intermediate, for any 

 adaptational reason whatever. The adaptation to their surround- 

 ings that is possessed by all living beings is primarily an internal 

 affair. Descending from ancestors not too far away in distance, 

 they presumably in most cases possessed an adaptation that was 

 not very difl'erent from that of their parents — at any rate those 

 that did not possess it would soon be destroyed by natural selec- 

 tion. The adaptation might cover a greater or slightly different 

 range of temperature or moisture, etc., that would enable them to 

 reach places unattainable by the parents, thus ensuring ultimately 

 a different distribution. 



All evidence goes to show that adaptation is rarely shown 

 in structural characters, and it will be of interest to draw up a 

 short list of some of those things that were considered as adapta- 

 tions in the writer's early days; hundreds more might be added: 



Phyllodes in Acacia 

 Thorny roots in Acanthorhiza 

 Reversed leaves in Alstroeyneria 

 Adventitious embryos 

 Self-burying fruit in Arachis 

 Hooked bracts in Arctium 

 Clasping hooks in Artabotrys 

 Cauliflory in Artocarpus 

 Pollinia in Asclepiadaceae 

 Thorns in Astragalus 



and many more in genera beginning with A. 



Red seeds in Paeonia 



Gutta-percha in Palaquium 



Horizontal fruit wing in Paliurus 



Scaly fleshy fruit in Palms 



Distribution by animals of stem joints in Panicum 



Distribution of Papaver seeds by pores in capsule 



Protogynous flowers in Paris 



Neuter flowers in Parkia 



Extrafloral nectaries in Passiflora 



Biennial life in Pastinaca 



and many more in genera beginning with P. 



It only requires that one should quote such cases as these, 

 which are not selected, but simply taken in alphabetical order 

 from my Dictionary, to show how the idea of universal adaptation, 



