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CHAPTER III. 



OF THE COMPOUND ORGANS IN FLOWERLESS PLANTS. 



We have now passed in i-eview all the different organs which 

 exist in the most perfectly formed plants ; that is to say, in 

 those whose reproduction is provided for by the complicated 

 apparatus of sexes and of fertilising organs. Let us next 

 proceed to consider those lower tribes, some of which are 

 scarcely distinguishable from animals, where there is no evi- 

 dent trace of sexes, in which nothing constructed like seeds 

 is to be detected, and which seem to have no other provision 

 made for the perpetuation of their races than a dissolution 

 of their cellular system. In what I may have to say about 

 them, I shall not, however, do any thing more than give 

 a mere enumeration and description of their organs. All 

 speculative considerations are in this case left out of view: 

 those who wish to be informed upon such points may consult 

 the " Introduction to the Natural System of Botany." 



1. Ferns. 



Filices, or ferns,^are plants consisting of a number of 

 leaves or fronds, as they are called, attached to a stem which 

 is either subterraneous or lengthened above the ground, some- 

 times rising like a trunk to a considerable height. They are 

 the largest of known vegetables in which no organs of fructi- 

 fication analogous to those of phaenogamous plants have been 

 discovered. Their petioles, or stipes {racliis, W. ; peridroma., 

 Necker), consist of sinuous strata of indurated, very compact, 

 fibrovascular tissue, connected by cellular matter ; and the 

 wood of those which have arborescent trunks is formed by the 

 cohesion of the bases of such petioles round a hollow or solid 

 cellular axis. The organs of reproduction are produced from 

 the back or under side of the leaves. In PolypodiacecB, or 

 what are more commonly called dorsiferous ferns, they ori- 



