OF THE LINN-SAN SYSTEM. 39 



but, at this time, the three orders of this perplexing 

 class are more readily found, and better arranged in 

 the two preceding classes. 



The last class of Linnaeus, or more properly grand 

 division of the vegetable kingdom, is called Crypto- 

 gam] a, from its invisible flowers and obscure fruit. 

 Neither stamens nor pistils, as in the other classes, 

 are here found. The natural divisions alone, then, 

 serve as ordinal distinctions, and four of these orders 

 are commonly adopted ; viz. 1st. The Filices, or 

 Ferns, by much the largest plants of the class, 

 some of them in tropical climates attaining the stature 

 of trees. 2d. Musci, the Mosses, having the fruit 

 of a very curious and complicated structure. 3d. 

 Alce, or Seaweeds, whose seeds or Spora are im- 

 mersed or hidden within some part more or less con- 

 spicuous of the substance of the plant. 4th. Fungi, 

 or Funguses ; such are the Mushroom and Puff-ball, 

 the impalpable dust of which last plant, specifically 

 light as air, consists of innumerable quantities of 

 germs, capable, like seeds, of regenerating individuals, 

 and that to almost any extent, if external circum- 

 stances were equally favorable. Indeed the lightness 

 and minuteness of the seeds or spora of this class of 

 plants may readily account for their occasional ap- 

 pearance in places and situations where they are 

 so little expected, that many among them have 

 been brought forward as common examples of the 

 existence of spontaneous vegetation. The indestruc- 

 tibility of many plants of this class is, also, nearly as 

 remarkable as the minuteness and prolificacy of their 

 spora. Many of the same Lichens and Seaweeds 

 are found in all situations, and in all climates, tropical, 

 as well as frigid ; and we have no reason, consequent- 

 ly, to believe that their means of increase and propa- 

 gation are less elusive or extensive. 



