146 Minnesota Plant Life. 



The peat-moss vegetative plant consists of a central axis 

 upon which are produced lateral leaf-bearing branches of two 

 kinds. Some of them protrude at an angle from the axis and 

 upon these the leaves contain leaf-green and are the starch- 

 making areas of the plant. Others with pale leaves hang limply 

 down along the axis, covering it and acting as conservators of 

 moisture. The leaf-bearing branches commonly stand very 

 close together forming a terminal tuft, and towards the end the 

 axis itself is sometimes branched repeatedly. At the very tips 

 of the branches, especially when they are young, a red or purple 

 dye often stains the leaves and the surface-layers of the stem. 

 This is a tvanning-up color and is useful as a device for raising 

 the temperature around the delicate cells of the growing buds. 



Formation of peat-bogs and coal. Peat-mosses are inher- 

 ently social plants as are the rest of their group, and they often 

 occupy large areas to the almost total exclusion of other kinds 

 of plants, except certain cranberries and heaths, pitcher-plants, 

 cotton-grasses and orchids which are to be sought in peat-bogs. 

 Every year the axes of the plants increase in length and the 

 older stems of former years sink lower into the bog. In this way 

 the centre of bogs, especially those fed by springs, becomes often 

 much higher than the circumference. Such raised peat-bogs 

 have been studied in New Brunswick and occur also in St. Louis 

 county, Minnesota. In such formations while one must ascend 

 to pass from the edge to the centre, yet the texture of the bog 

 becomes looser as the margin is left behind. When peat-moss 

 has been growing thus for many centuries, filling what was once 

 perhaps a lake, the remains of the old stems become matted 

 together by the pressure of the heavy water-logged fresh areas 

 above and after a time such a mass becomes compacted into 

 what is known as peat — probably one of the stages in the pro- 

 duction of coal. It is by no means certain that coal was devel- 

 oped from mosses like the living peat-mosses, Init it is alto- 

 gether certain that it originated in ancient swamps by the same 

 general process which is to-day building the peat-bogs. So, some- 

 what as iron-bacteria deposited beds of iron ore in ancient warm 

 oceans, mosses and other plants in the illiniiiablc swamps of the 

 coal age contri1>utr(l their part to modern human industry. 



