BRYOPHYTES 



FIG. 248. Sphagnum: stem bearing a 



initial. The mature archego- 

 nium is stalked, with a massive 

 venter, a long and often twisted 

 neck, and numerous neck canal 

 cells (fig. 249). 



Sporophyte. The sporophyte 

 (fig. 250) develops at first by a 

 series of transverse walls until a 

 short filament is formed, which 

 later becomes massive by means 

 of vertical walls. The upper tiers 

 develop the capsule, which is 

 organized as in Anthoceros, with 

 the endothecium developed as 

 the axial columella, with the 

 sporogenous tissue cut off as an 

 inner layer (becoming four 

 layers) of the amphithecium 



and Capping the Columella like terminal cluster of sporophytes, showing the 



a dome, and with a wall of five position of archegonia. 



to seven layers. These Anthoceros-like features are further emphasized 



by the large bulbous foot and the rudimentary seta, which is only a 



necklike connection between capsule #nd 

 foot, and is often called the neck. Very 

 important differences, however, are as 

 follows: (i) there is no such development 

 of chlorophyll tissue in the wall of the 

 capsule as characterizes Anthoceros; (2) the 

 neck is not a growing region, and hence 

 the capsule does not elongate ; and (3) the 

 capsule dehisces by a definite lid (oper- 

 culum), which is distinctly a moss character. 

 As in all bryophytes, during the develop- 

 ment of the sporophyte the venter of the 

 FIG. 249.' Sphagnum: sur- archegonium develops the encasing calyptra, 



face view of three archegonia; w r hich in Sphagnum is ruptured by the 



the middle archegonium shows g ro \ving capsule, 

 the spiral direction of the cell 



rows of the neck. After A peculiar feature of Sphagnum is the 

 SCHIMPER. pseudopodium, which is a structure replac- 



C. B. & C. BOTANY 8 



