MOSSES WITH A HAND-LENS 5 



Life History and General Structure. 



| HE fruiting moss plant consists of two distinct parts, 

 the green leaf-bearing portion and the spore-bearing 

 part a slender bristle-like seta (sometimes almost 

 lacking), bearing at its summit the capsule which con- 

 tains the spores. The main use of the seta is to bear the 

 capsules up above the surrounding plants to get light and air, and 

 especially to place the spores where they will readily be dis- 

 tributed by the wind. 



If you shake the freshly ripened capsule of any of the larger 

 mosses you can easily see a small cloud of fine powder the 

 spores. If you mount such a capsule in water and press down 

 upon the cover the mass of escaping spores can readily be seen. 



When the spores fall on moist earth, under favorable condi- 

 tions, they germinate by sending out tiny green threads called 

 protonema ; these continue growing until a green felt-like cover- 

 ing is formed over the bare soil or other substratum. From this 

 protonema grow the moss plants. 



If one examines damp earth that has been undisturbed for a 

 few months he will readily find this green felt with tiny moss 

 plants sticking up here and there. Greenhouses and old gardens 

 are particularly good spots to search for this purpose. If one is 

 fortunate enough to find fresh plants of the Slender Pogonatum 

 the green protonema will be very conspicuous. 



On the leafy portion of trie plant are borne male and female 

 reproductive organs, antheridia and archegonia. From the fertil- 

 ized egg-cell in the archegonia develops the spore-bearing part 

 the sporophyte or sporogonium. 



It is just as necessary that the spores of mosses be widely 

 distributed as it is that the seeds of flowering plants be scattered 

 far and wide, and very similar means are employed. The cap- 

 sules of the Peat Mosses explode and shoot the spores as much 

 as four inches into the disturbing breeze or onto the hair of pass- 

 ing animals. Webera and Buxbaumia are miniature powder guns 

 fired by falling rain drops or by passing insects or other small 

 animals. 



By far the greater number of capsules are like miniature 

 pepper boxes, shaking their life-bearing powder onto every breeze 

 .and shaken by every puff of wind and every passing object. 



The mechanism of the boxes is most wonderful. The seta 



