8 M. Morren on the Spur-shaped Nectaries 



Let us see, first, what takes place in a flower of Aquilegia 

 vulgaris calcarata. 



1. Metamorphosis of the stamen into a spur-shaped nectary. 



The stamen of the Columbine has a thread-shaped filament 

 slender, flexible and yellow, and a two-celled anther with pa- 

 rallel cells, slightly swelled, opening with a slit and united by 

 a narrow connective, the whole yellow. The connective is 

 even hardly visible (Plate XL fig. 1). 



In many flowers, we find along the spire which leads in- 

 sensibly from the androeceum to the corolla, stamens which 

 turn into nectaries. To bring this about, the filament en- 

 larges at its base; the connective is, at the opposite pole, 

 the other organ which becomes modified, and it is even the 

 most active of all in this transformation. It enlarges above, 

 by separating the two loculi of the anther, and it grows to a 

 point. This is not slow in becoming bifurcate, so that the 

 connective is soon bilobate. (Figs. 2 and 7«) 



To this modification, which up to this period does not at- 

 tack the regularity of the organ, two ways of transformation 

 succeed. In the one, one of the loculi of the anther disap- 

 pears, in the other it remains visible with its fellow. The 

 first of these modifications might induce a belief that the spur 

 is a sac formed by one half of an anther or by a loculus, but 

 this genesis is but a deceitful appearance. The second way 

 of transformation proves that the spur is a sac-shaped con- 

 nective, and that the two lobes of its limb represent the two 

 loculi of the anther originally united by this same connective. 



If such a spur-shaped nectary can be obtained, as from its 

 nectar-secreting gland is truly a nectary, and that in it the 

 two lobes of its limb exist as an elongation of the two an- 

 ther-cells, still visible enough to attest their presence, it is 

 clear that this second way of transformation should be ad- 

 mitted. Now this is precisely what experience confirms. In 

 the Columbine we find this form, not so frequently as the 

 first, it is true ; but it is found, and that is all that is neces- 

 sarj^ This case we have delineated (Plate VII. fig. 6). On a 

 stamen thus modified, besides a well-formed filament [c h), 

 we find the tw^o loculi of the anther, still bearing pollen, but 

 which open more widely [a b), separated by a small connec- 

 tival eminence (c). Each of the swellings which represent the 

 anther-cells produces an elongation in form of a thick margin 

 {e), which, reaching from the inside to the outside, goes to 

 form the circumference of the two lobes of the cornet {d g), 

 separated by a slit {f). Each lobe corresponds to a cell, and 

 originates from it ; it is only indeed that same cell length- 



