4 yo THE POPULAR SCIENCE MONTHLY. 



to vegetate is a ceaseless power. It has been in operation from the 

 earliest ages of the earth, ever since living beings were capable of ex- 

 isting upon its surface ; and so active in the past history of the globe 

 has been this tendency, that most of the superficial rocks of the earth's 

 crust are composed of the remains of plants. It operates with un- 

 diminished and tireless energy still. Vegetation takes place upon 

 almost every substance ; upon the bark of trees, upon naked rocks, 

 upon the roofs of houses, upon dead and living animal substances, 

 upon glass when not constantly kept clean, and even on iron which 

 had been subjected to a red heat a short time before. Zoologists tell 

 us, when speaking of animalcules, that not a drop of stagnant water, 

 not a speck of vegetable or animal tissue, not a portion of organic 

 matter, but has its own appropriate inhabitants. The same may be 

 said of plants ; for we can hardly point to a single portion of the 

 earth's surface which is not tenanted by some vegetable form whose 

 structure is wonderfully adapted to its situation and requirements. 

 Even in the hottest thermal springs, and on the eternal snows of the 

 arctic regions, peculiar forms of vegetation have been found. From 

 the deepest recesses of the earth to which the air can penetrate, to the 

 summits of the loftiest mountains ; from the almost unfathomable 

 depths of the ocean to the highest clouds ; from pole to pole, the vast 

 stratum of vegetable life extends ; while it ranges from a temperature 

 of 35 to 135 Fahr., a range embracing almost every variety of con- 

 ditions and circumstances. 



The most cursory and superficial glance will recognize in every 

 scene a class of plants whose singular appearances, habits, and modes 

 of growth, so prominently distinguish them from the trees and flowers 

 around, that they might seem hardly entitled to a place in the vege- 

 table kingdom at all. On walls by the wayside, on rocks on the hills, 

 and on trees in the woods, we see tiny green tufts and gray stains, or 

 party-colored rosettes spreading themselves, easily dried by the heat 

 of the sun, and easily revived by the rain. In almost every stream, 

 lake, ditch, or any collection of standing or moving water, we observe 

 a green, slimy matter, forming a scum on the surface, or floating in 

 long filaments in the depths. On almost every fallen leaf and de- 

 cayed branch, fleshy, gelatinous bodies of different forms and sizes meet 

 our eye. Sometimes all these different objects appear growing on the 

 same substance. If we examine a fallen, partially-decayed twig, half- 

 buried in the earth in a wood, w T e may find it completely covered with 

 various representatives of these different vegetable growths ; and 

 nothing surely can give us a more striking or convincing proof of the 

 universal diffusion of life. All these different plants belong to the 

 second great division of the vegetable kingdom, to which the name of 

 Cryptogamia has been given, on account of the absence, in all the 

 members, of those prominent organs which are essential to the pro- 

 duction of perfect seed. They are propagated by little embryo plants 



