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ceived would have otherwise formed the peristome, being carried up 

 from their usual position, simply in consequence of the elongation of 

 this organ. 



It might be thought that the number of leaves on the axis ought to 

 be the same, and not less than those constituting the peristome. But 

 when the thirty-two leaves, which ought to have preserved the same 

 plane, in order to form the peristome, are changed to an entirely dif- 

 ferent purpose, and become arranged on an axis which may elongate 

 indefinitely, which elongation was suddenly arrested by taking the 

 moss from the case, the specimens cannot offer anything decided on 

 this point. This variation from the ordinary structure of the repro- 

 ductive apparatus of a moss, fully bears out the views of Professor 

 Lindley, on certain points, viz., those which relate to the calyplra, 

 operculum and peristome ; but it is not clear to me that the theca is 

 the hollowed out apex of the stem. In the first part of this paper it 

 was mentioned, that in certain monstrosities, such as the conversion 

 of the carpellary leaves into petals, that the first act of destroying 

 the seed-vessel, as in Lychnis dioica, and the " double cherry," was 

 frequently to occupy its site by certain greenish leaves, not then pe- 

 taloid ; here we find an analogue to that which happens in mosses. 

 The ripened capsule of a Lychnis is not unlike that of a moss, being 

 urn-shaped, possessed of a certain number of teeth at the mouth, and 

 having a central placenta, the representative of a columella within. 



This organ can be entirely transformed into leaves, no one, in this 

 plant, supposing it to be the hollowed out apex of the stem ; therefore I 

 am inclined to believe that if carpellary leaves are employed to form 

 the peristome of mosses, of which there can be scarcely a doubt, that 

 it is their apices which constitute this portion, and that others, by 

 their united edges, form the theca. 



When the floral organs of the higher order of plants are examined, 

 an involucrum, calyx and corolla, besides the sexual organs, are oc- 

 casionally found in the same flower ; others more commonly possess 

 calyx and corolla only, but many only a calyx. When we examine 

 the fructification of mosses, it is found that the most simple have no 

 peristome, that others have a single peristome, and that certain others 

 have a double peristome. From the delicate dissections of these parts, 

 by Valentine and others, it is shown that the peristome is connected 

 with a membrane lining the theca, and does not spring immediately 

 from its margin, showing that there are two organs, one within the 

 other. This fact makes me consider the theca and operculum to be the 

 representatives of a consolidated calyx, and that the corolla is the lining 



