SOIL FORMATION : MOORS. 393 



conifers. As the branches die, the free ends curve downward 

 more and more, all gradations being presented in a single tree. 

 A group of such dying spruce trees is shown in fig. 487. Some 

 have been long dead ; only the knotted, weather-beaten trunks 

 still remain tottering to their final condition. Others with leaf- 

 less, dried, sprawling branches go swirling with every wind, 

 while a few struggle on in the presence of these untoward con- 

 ditions. 



708. Other morainic moors. — In other basins, where the 

 hills on all sides are still forest-clad, more equable temperature 

 and moisture conditions are conserved. This permits plants to 

 flourish here which in the exposed basins are disappearing from 

 the formations or only leading a miserable existence. This is 

 strikingly true of some sphagnum formations. In the atoll for- 

 mation described the evidence suggests that sphagnum formerly 

 played a more active part in the evolution of that type of moor 

 than has been the case since the hills were denuded of their 

 trees. So also in the spruce moor, sphagnum probably was at 

 one time a prominent factor in the formation of the early vege- 

 tation. But excessive drought during certain seasons, and full 

 exposure to the sun and wind, have served to lessen its influence 

 and importance. But where protected from the wind, to a large 

 extent from the heat of the sun, and supplied with a suitable 

 moisture condition, the sphagnum flourishes. It grows either 

 alone in shallow water, encroaching more and more on the center 

 of the basin, or follows after and anchors among water-loving 

 grasses and carices. In some cases it may thus largely cover 

 such earlier formations. An examination of the sphagnum 

 plant shows us how well it is adapted to flourish under such 

 conditions. The main axis of the plant bears lateral branches 

 nearly at right angles, but with a graceful downward sweep at 

 the extremity. These primary lateral branches bear secondary 

 branches, which arise, usually several, from near the point of 

 attachment to the main axis. They hang downward, overlap on 

 those below, and completely cover the main axis or stem. The 

 leaves of sphagnum are peculiarly adapted for the purpose of 



