14 THE EQUISETACE>. 



The spores are tiny globular, single-celled bodies, 

 bright green in colour, and so small that single indi- 

 viduals cannot be distinguished without a lens. Each 

 two filiform appendages with enlarged ends, 



called elaters, 

 w h i c h are at- 

 t a c h e d to the 

 equator of the 

 spore by their 

 middle, coiling 

 spirally around it 

 when moist and 

 spreading out 

 when dry. As 

 the spore - case 

 dries at maturity, 

 the elaters uncoil 

 and assist in 

 SPORES, ENLARGED. liberating t h e 



spores; and when the spores are free, they assist in float- 

 ing them on the air. The elaters of several spores 

 often become entangled, and the spores float away to- 

 gether, an advantageous arrangement, since the prothallia 

 are dioecious and require more than one spore to repro- 

 duce a plant. 



The spores contain chlorophyll, the green colouring- 

 matter of plants, and lose their power of germinating 

 within a few days after leaving the spore-case. When 

 they lodge in a favourable place, they germinate in ten or 

 twelve hours, and soon produce small green, lobed pro- 

 thallia. It is said that the fresh spores will germinate 

 readily if sown upon the surface of water. Although 

 the spores are apparently all alike, some produce only 



