FROM THE COROLLA. 449 



of alternation) that suppression of certain organs has 

 taken place. 



Taking first those instances in which the supple- 

 mentary petals appear on the inner surface of the 

 corolla, as being at once the most frequent, and as 

 presenting the closest analogy, with similar conforma- 

 tions, under natural circumstances, certain double- 

 flowered varieties of the Chinese primrose, Primula 

 sinensis, may be mentioned. In these flowers the calyx 

 is normal, the tube of the corolla is traversed by ten 

 vascular bundles, and the Hmb is divided into ten fimbri- 

 ated lobes. About halfway up the tube, on the inner 

 surface, are given off" five supernumerary petals, opposite 

 to as many lobes of the corolla. Some of the supple- 

 mentary petals have a stamen in front of them, in the 

 same relative position as in the normal flower. In 

 some cases the back or outer surface of the supple- 

 mentary petal is turned towards the inner or upper 

 surface of the primary corolla, thus ;^ ; while, in other 

 instances, the front of the adventitious lobe is directed 

 towards the corresponding surface of the original petal, 

 thus CZ^. Whether these supernumerary petals are 

 formed by chorisis or by enation cannot, with cer- 

 tainty, be determined without examining the early 

 stages of development. 



Of more interest are those instances where the ad- 

 ventitious growth is on the outside of the coroUa ; thus, 

 in a garden azalea there was intermediate between the 

 calyx and the corolla, both of which were normal, a 

 series of five petalodes, alternating with the sepals, and, 

 therefore, opposite to the lobes of the corolla, and 

 adherent with them at the very base, though elsewhere 

 detached. These petalodes were concave on the surface 

 looking towards the calyx, and were there brightly 

 coloured, while the tint of the opposite surface looking 

 towards the corolla was of a duUer hue, corresponding 

 with that of the outside of the corolla-tube. This 

 arrangement of the colour was thus precisely similar 

 to that which occurred in the four-winged leaves 



29 



