Minnesota Plant Life. 



153 



Spore-distribution by mosses. Before closing the account 

 of the mosses it wih be profitable to examine somewhat more 

 fnllv the methods of spore-dissemination which are employed 



by the high- 

 ly developed 

 forms, and 

 ' the carpet- 

 mosses may 

 be chosen as examples. Here the plant- 

 body is variously branched, the branches 

 being interlaced and the whole spread 

 out in a soft green turf. On some of the 

 lateral branches rising vertically into the 

 air are borne the capsular plants. Their 

 slender stalks are of a reddish-brown col- 

 or and if closely scrutinized will be found 

 to be twisted or fluted. They are an inch 

 or more in length and at the end, nodding 

 strongly to one side, is the slender urn- 

 shaped capsule with a distinct lid. The 



cells of the 

 wall where 

 ^ the lid joins 

 the urn are 

 peculia rly 

 flat and low, so that when the proper con- 

 ditions of moisture are at hand the urn 

 easily cuts off its lid and on account of 

 the inclined position of the capsule opens 

 its mouth towards the side. The greater 

 portion of the mouth of the urn is closed 

 by a plug consisting of the end of the 

 central strengthening column, and only 

 a narrow circular slit between this plug 

 and the wall is left through which the 

 spores may be sifted out. After the lid 

 has fallen two rows of curious, sler^er teeth are seen to pro- 

 ject outside the circular slit arching over it toward the cen- 

 tre. These teeth are very sensitive to moisture and when 



Fig. 48. A moss leafy-plant, 

 with prostrate propagative 

 branch and erect female 

 reproductive branch. On 

 the latter two egg-organs 

 have developed their eggs 

 into capsular plants, one 

 of which is ejecting spores. 

 The two round bodies are 

 spores much magnified. 

 After Atkinson. 



