GENERATIVE APPARATUS OF MABCHANTIA. 



369 



Archegonia of Marchantia polymor- 

 pTia, in successive stages of develop- 

 ment. 



Antheridium, composed of a mass of Sperm-cells, within which 

 are developed Antherozoids like those of Chara (§ 255), and sur- 

 mounted by a long neck that projects through the mouth of the 

 flask shaped cavity. The 



wheel-like receptacles (Fig. Fig. 179. 



176), on the other hand, bear 

 on their under surface, at an 

 early stage, concealed between 

 membranes that connect the 

 origins of the lobes with one 

 another, a set of Archegonia, 

 shaped like flasks with elon- 

 gated 'necks (Fig. 179); each 

 of these has in its interior a 

 Grerm-cell, to which a canal 

 leads down from the extre- 

 mity of the neck ; and there 

 is every reason to believe that, 

 as in Ferns, the germ-cell is 

 fertilized by the penetration 

 of the Antherozoids through 

 this canal until they reach it. 



Instead, however, of at once evolving itself into a new plant resem- 

 bling its parent, the fertilized germ-cell or Embryo-Cell developes 

 itself into a mass of cells enclosed within a capsule, which is termed a 

 Sporangium ; and thus the mature receptacle, in place of Archegonia, 

 bears capsules or Sporangia, which finally burst open and discharge 

 their contents. These contents consist of Spores, which are isolated 

 cells enclosed in firm yellow envelopes ; and of Elaters, which are 

 ovoidal cells, each containing a double spiral fibre coiled up in its 

 interior. This fibre is so elastic that, when the surrounding pressure 

 is withdrawn by the bursting of the Sporangium, the spires extend 

 themselves (Fig. 180), tearing apart the cell-membrane ; and they do 

 this so suddenly as to jerk forth the spores which may be adherent 

 to their coils, and thus to assist in their dispersion. The Spores, 

 when subjected to moisture, with a moderate amount of light and. 

 warmth, develope themselves into little collections of cells, which 

 gradually assume the form of a flattened Frond; and thus the 

 species is very extensively multiplied, every one of the mass of 

 Spores, which is the product of a single Germ-cell, being capable of 

 giving origin to an independent individual. 



275. The tribe of Mosses is as remarkable for the delicacy and 

 minuteness of all the plants composing it, as other orders of the 

 Vegetable Kingdom are for the majesty of their forms, the richness 

 of their foliage, or the splendour of their blossoms. There is not 

 one of this little tribe whose external organs do not serve as 

 beautiful objects when viewed with low powers of the Microscope ; 

 while their more concealed wonders are admirably fitted for the 



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