STRUCTURE OF FLOWERS. 89 



other Monochlamydeous families have perigynous sta- 

 mens, and the torus consequently adherent to the 

 calyx. Finally, whether we say that it is a calyx, or 

 that it is a double one with a petaloid lamina, all the 

 consequences are found the same, and therefore the 

 difference is of but little importance. 



We shall now examine the envelope of Monocotyle- 

 donous flowers, and here we shall find some new diffi- 

 culties. Desvaux, considering that it is always formed 

 of two rows of pieces placed alternately, has proposed 

 to consider the outer one as a calyx, and the inner one 

 as a corolla. This mode of viewing it seems particularly 

 authorized : — 1st, by the structure of the Commelineas, 

 Alismacese, and several Amomeae, where the outer row 

 has a perfectly calycine appearance, and the inner one a 

 perfectly petaloid one ; 2d, because the aestivation of 

 the two rows is often very different, as, for example, in 

 Tradescantia, where that of the outer row is valvate, and 

 that of the inner irregularly twisted. This manner of 

 expression would often be advantageous for the clearness 

 of descriptions ; but as to the reality, it appears to me 

 hardly admissible: in fact, in the majority of cases these 

 two rows are perfectly similar, and especially in all 

 Liliaceous plants with an adherent ovary, the two rows 

 are equally united to that organ, whilst true corollas 

 never are. It must then be admitted, that the two rows 

 form part of a single envelope, which Linnaeus calls 

 corolla, Jussieu calyx, and I perigone. 



The reasons which I have above mentioned, and 

 especially the adhesion with the ovary, prove that it is 

 not a true corolla. The idea of considering it as a calyx 

 presents the same difficulties which I have shown in 

 monochlamydeous Dicotyledons ; and, moreover, in these 

 two circumstances: — 1st, that the stamens are most 

 frequently hypogynous ; 2d, that when the flowers 



