of the Aquilegia vulgaris. 15 



loid form of tlic petals of these varieties to their being formed 

 only by the filaments of modified stamens in ■which the an- 

 thers are abortive. This Avould be an hypertrophy of the sta- 

 minal filaments. We would not venture to say that this is 

 exact : on the contrary, we think that the petaloid and not 

 cueulliform laminae of the stellated Columbines are also in 

 reality only modified connectives, and we rest this opinion 

 on the fact that the genesis of these laminae presents in the 

 young flowers the same primary forms as the cornets : these 

 are at first stamens without filaments, but with enlarged 

 anthers. This point alone is decisive ; but upon the Aqui- 

 legia atrata we have often found flowers where the laminae 

 form their spur by slow degrees. This spur, at first a cavity, 

 afterwards a canal, then a tube, then at last a cornet, ori- 

 ginates at the base of the laminre, so that the greater part of 

 these represent the two lobes of the cornets of the Aquilegia 

 vulgaris calcarata, which lobes we have shown to be nothing 

 but the extensions of the two anther-cells. We think, there- 

 fore, that it is to the anther also that the petaloid lamina is 

 owing. On a flower of the Aquilegia atrata we have seen a 

 well-formed lamina without a trace of spur ; the following one 

 had a simple protuberance, the third a tube, the fourth a half- 

 spur, and the fifth an entire spur. Ail this was the result of 

 a simple elongation of the base of the lamina: now, if this 

 were not an anther in its nature, it would be difficult to ad- 

 mit that the filament could produce the same organs as the 

 anther, and the more so as the facts previously established 

 prove that the gland represents, as to function, the pollen- 

 bearing loculus, and the nectar the pollen, whilst the cornet 

 is really the connective. The filament, when it suffers hyper- 

 trophy, as is the case in the white lamellae near the carpels, 

 gives birth to no pi'oduct ; whilst, on the contrary, the peta- 

 loid laminae produce a nectary, and subsequently nectar. Or- 

 ganogeny, morphology, and the metamorphoses, unite then in 

 leading us to think, that in the stellated Columbine the spurless 

 petals are modified anthers and not filaments, and capable, as 

 such, of elongating themselves directly into spur-shaped nec- 

 taries under many circumstances. 



EXPLANATION OF PLATE XL 



Fig. 1 — 8. Metamorphoses of the stamen into a spur-shaped nectary. 

 Fig. 8 only is of the natural size ; the others are magnified three 

 times in diameter. 



Fig. 2. Stamen at its first period of metamorphosis. 

 a. Lengthened connective. c. Anther-cells. 



h. Bind point of the connective. d. Filament. 



