FROM THE COROLLA. 44.9 
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 
simensis, may be mentioned. In these flowers the calyx 
is normal, the tube of the corolla is traversed by ten 
vascular bundles, and the limb 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 <>. 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 corolla; 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 duller 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 
