STEMS OF CRYPTOGAMIA. Ill 



" The fig-tree : not that kind for fruit renowned ; 

 , But such as at this day to Indians known 



In Malabar or Deccan, spreads her arms, 

 Branching so hroad and long, that in the ground 

 The bending twigs take root, and daughters grow 

 About the mother-tree, a pillar'd shade, 

 High overarch'd, with echoing walks between." 



153. The only Cryptogamia at present existing, which form 

 true woody trunks, are the Tree- Ferns of tropical climates. In 

 these, the stems which creep along or under the ground, in the 

 species inhabiting temperate climates, erect themselves into the 

 air, and bear a beautiful crown of leaves. These stems are some- 

 times hollow, and sometimes contain a sort of spongy pith. Their 

 mode of growth is different from that of either 

 Exogens or Endogens ; and appears of a simpler 

 character. The stem, when cut across, is seen 

 to consist of a number of hard woody plates, 

 adhering rather loosely together ; and these, if 

 traced upwards, are found to be either continu- 

 ations of the flattened footstalks of the leaves 



FIG. 58. PORTION 



which crown the summit, or to be the remains OF THE STEM OF A 



of those which have dropped off. Every year, ca^'of former 



the leaves decay away, and are replaced by a ^aves. 

 new set formed above ; so that the stem continues increasing in 

 length, but undergoes little change in diameter. The marks 

 seen on the exterior of the trunk, are the scars of the former 

 leaves ; and by the relative position of these, it is seen that, 

 though the portion of the stem first formed increases but little in 

 diameter, it receives some addition to its length, its scars being 

 separated from each other by a much wider interval, than in the 

 newly-formed part. However, it is the general rule, in these 

 and other Cryptogamia, that the portions first produced undergo 

 little subsequent change; hence, whilst the names Exogens and 

 Endogens are used, to indicate the modes of growth respectively 

 peculiar to the two chief divisions of Flowering plants, the 

 Flowerless plants may be included under the general term ACRO- 

 GENS, which intimates growth by the point, or by addition to 

 the extremities only. 



