1053 



VEGETABLE ORGANOGRAPHY. 



irregularity in the others. Let us follow the application 

 of these principles to the different organs of the flower, 

 and to the different kinds of irregular flowers. 



The sepals, in consequence of their foliaceous nature 

 and external position, are more liable than all the other 

 organs to the action of external causes ; thus we find 

 irregular calyces even in flowers otherwise regular ; thus 

 one of the free portions of the sepals of Musscenda and 

 Pinckneya is spread out into a limb much larger than 

 the other. The same phenomenon takes place, although 

 in a less decided and constant manner, in Roses. 



The petals present inequalities of size, which result 

 from the unequal development of the neighbouring 

 sepals, or from the different modes of their metamor- 

 phosis. 



The pieces of the calyx, corolla, or perigone, are often 

 united together in unequal degrees ; when the inner or 

 upper pieces are united at a different point from where 

 the lower ones cohere : it results that the flower has two 

 lips, an upper and lower one ; and it is so true that the 

 flowers with a labiate calyx or corolla owe this irregu- 

 larity to their position with regard to the axis, that we 

 never find the lips lateral, but always superior and 

 inferior, as we see in the labiate calyces of the Pa- 

 pilionaceae, Labiatas, Scrophularineae, &c, in the co- 

 rollas of the two last families, or the perigones of the 

 Orchideas, &c. 



The stamens are organs very subject to irregularity, 

 even in plants where the rest of the structure is regular : 

 it must, however, be remarked, that they may be un- 

 equal with regard to each other without being irregular; 

 thus, in several flowers which have the number of 

 stamens double that of the petals, they are alternately 

 long and short, early or late in coming to perfection ; 

 and in this case, it is those which alternate with the 



