228 



PLANT LIFE. 



cells. Mixed with the spore-producing cells, however, are 

 many sterile cells, which become gradually elongated, and 



ch 



nt 



FIG. 230. FIG. 231. 



FIG. 230. The sporophyte of a peat moss, (Sphagnum actitifoliuni) with adjacent parts 

 of the gametophyte. The sporophyte consists of a capsule, .r.v, and a broad foot, sg' . At 

 the stage shown in B it is still completely enclosed in the tissues of the gametophyte, 

 viz., c, the enlarged ovary which forms the calyptra or hood, and ?', the vaginule or 

 sheath surrounding the foot, ar is the neck of the ovary. (Compare fig. 331.) The 

 arc over the large-ceiled central tissue (columella) is the sporangium, ps, the false 

 stalk, produced by the gametophyte, which raises the sporophyte. In A, the calyptra 

 has broken, only a fragment remaining, exposing the capsule. </, the lid, by whose fall 

 the sporangium is exposed and the spores escape, ch, leaves of the gametophyte : </s, 

 the false stalk. Compare figs. 67, 72, 73, in which the stalk is part of the sporophyte. 

 A magnified 13 diam.: />, 32 diam After Schimper. 



FIG. 231. Longitudinal section of the young capsule of a true moss (Bryiou). s, spo- 

 rangium. At this stage the mother cells of the spores, sfn, have become free (only a 

 few are shown still enclosing the spores) ; siu, the wall of the sporangium, lined by 

 the remains of another layer of cells now disorganized ; c, the columella, of partly col- 

 lapsed cells ; is, intercellular space ; cu>, wall of the capsule ; an, the annulus, a ring 

 of cells which pries off the lid, at whose edge they develop ; ot, the outer, m, the inner, 

 peristome, formed by the thickening of parts of the walls of certain rows of cells ; nt, 

 nutritive tissue, with chloroplasts and intercellular spaces. Magnified 25 diam. Orig- 

 inal. 



