182 PHILOSOPHICAL NOTES ON 



teeth of the rose-leaf are now inherited as atrophied branches, 

 although thej are of no conceivable use whatever. Lathyrus 

 tuherosus may have been one of those fortunate beings who had 

 " two strings to its bow," for it is both an annual^ as far as its 

 lea,ves and flowers are concerned, and also a perennial, through its 

 roots. 



The flowers of orchids have also undergone great modifications, 

 and in these plants also we find storage organs, both in the 

 terrestrial and in the arboreal species. The fact that in terrestrial 

 forms the storage occurs in the so-called roots, and in the arboreal 

 forms in the so-called stem, brings us a step nearer towards 

 accepting the notion that the stem and root are only modified 

 forms of the same thing. 



I am aware that the potato has tubers, although its flowers 



have not undergone so great a modification as that of the pea. 



Now I am not, however, arguing the case of the potato but rather 



that of the pea, and my suggestion in no way excludes the 



possibility of a hundred other reasons, why other plants have 



evolved storage organs. It is quite conceivable that every group 



of plants with a common descent may have had its own reasons for 



having acquired storage underground organs, whether we call 



these a bulb, a corm, a tuber, a tubercle, or a fleshy root. 



We might conceive three forms of leguminiferae : 



(«.) Those in which the storage tubercles were fully developed 



and the plant practically perennial, reproducing itself every 



season by underground buds. It may have been that the 



flowers and seeds were imperfectly developed, or it may have 



been that the above-ground portion was eaten up by animals, 



and had no chance of reproducing itself.* Therefore, the 



only hope of that particular species being continued would 



have been in its re-appearing through the dormant life of its 



roots or underground branches. f 



{b.) Those in which, while the underground tubercles still 



continued to play their part with vigour, the flowers and seeds 



* The immense herds of herbivora we hear of, and the clouds of locusts 

 which often settle on the land, would devour everything green in a very short 

 time. 



f In other words it had to live an underground \\i(d,hiding itself irom the 

 cold and other enemies with the chance of better luck next season. 



