INTRODUCTION. 



the fruit. The last pair, or more, of leafy expan- 

 sions immediately beneath the perianth, whatever 

 their form, are the perichsetial leaves or bracts. 

 Within these are to be found the arcJiegonia or, as 

 sometimes called, the pistillidia, indefinite in 

 number, perhaps three, or as many as ten, of which 

 only one or two are fertilized and develope into the 

 perfect fruit. The archegonia, therefore, are the 

 young female organs of reproduction, and arise 

 usually from the apical cell of the axis or in close 

 proximity thereto. After the appearance of the 

 archegonia a simple cellular ring indicates the com- 

 mencement of growth of the colesule or perianth, 

 which is always subsequent to the formation of the 

 archegonia. When the colesule is developed it en- 

 closes the fertilized and the sterile archegonia with 

 all their subsequent appendages. 



Passing over the intervening period we arrive at 

 the time when the cole- 

 sule, or perianth, is fully 

 developed and half emer- 

 gent from the perichaetial 

 leaves (as in fig. 10), with 

 an apiculus at the apex or 

 wholly emergent from a 

 whorl of bracts (as in fig. 

 n) and toothed at the 

 apex. We need not ad- 

 vert here to the various 

 modifications of this peri- 

 anth or colesule, which is often plicate, or angular, 



