154 Notes on Indian Botany. 



ly situated^ it of course behoves me in the present instance 

 to follow in their footsteps and add a genus to the order, 

 merely differing from Doronicum in the disk ; the achaenia 

 being bald, while in it, they are crowned with pappus. 



This reasoning from analogy, seems rather an arbitrary 

 proceeding, as it is admitted by all botanists, that the pappus 

 is simply the limb of the calyx modified by peculiar circum- 

 stances, causing it to assume various shapes in different 

 species; while its absence is attributed to its growth being 

 arrested by the pressure of the surrounding parts. 



In the case of Doronicum and some others, this mode 

 of accounting for its absence seems scarcely satisfactory, as it 

 is difficult to imagine how a greater pressure should be 

 exerted on the outer ray florets, in which only it is deficient, 

 than on the disk ones. Neither can I imagine how, in plants 

 so much alike in all their external features as those now 

 under consideration, that organ should present such varia- 

 tions, the assigned cause being the same in all. These exam- 

 ples lead to the inference, that the endless variations observed 

 in this organ, viewed in connexion with their constancy 

 in each species, are referable to the operation of some other 

 and higher cause than mere pressure of the surrounding 

 parts, which can scarcely be supposed to act so uniformly as 

 the constancy of the effect indicates. I do not wish it to be 

 inferred from these remarks, that I would go so far as to deny 

 that pressure, in the manner supposed, exerts powerfully 

 modifying effects on parts exposed to its action : I merely 

 wish to hint that there is ground for questioning the correct- 

 ness of the theory to the extent claimed for it by its sup- 

 porters. 



Taking this view of the matter, I willingly accord a high 

 value to characters derived from the pappus, higher perhaps 

 than I should feel inclined to yield, could I persuade myself to 

 look upon it simply as the limb of the calyx, modified in its 

 development by the pressure of surrounding parts. Senecio and 



