The Transition from the Cryptogams to the 

 Phanerogams. 



All the plants considered in the preceding chapters are included 

 in the term CRYPTOGAMS; all in the following chapters under the 

 head of PHANEROGAMS (see page 3). Hoffmeister's pioneer works 

 (Ibol, Vergleichende Untersuchungen der hiJhereu Kryptogamen, etc.) 

 and the numerous researches published later by other investigators, 

 have closed the gap which was formerly thought to exist between 

 these plants ; so that we now, in the series : Bryophyta Pterido- 

 phyta Grymnospermse Angiosperm.se see the expression of a 

 single line of development in accordance with a definite plan. The 

 forms through which this gradual development has taken place 

 have in course of time, however, to a great extent died out, and 

 only single links of the chain connecting the lowest to the highest 

 still remain. 



THE ALTERNATION OF GENERATIONS, which we found indicated in 

 certain Thallophytes, can be proved with the greatest clearness in 

 all the higher Cryptogams, from the Mosses upwards; it is also 

 found in the Phanerogams, but not in such a pronounced degree, 

 because one of the generations is so far reduced that it has almost 

 given up its independence. For the sake of greater clearness, we 

 will begin with the comparison of the sporophyte, asexual (second) 

 generation. 



The asexual (and) generation of the Cormophytes. 



The asexual generation which follows from the further develop- 

 ment of the fertilised oosphere, is, in the Mosses, only the sporo- 

 gonium (according to one theory it is perhaps homologous with a 

 spore-bearing leaf, situated upon a short stem, see p. 187) ; in 

 Filicince, Equisetince, and Lycopodinw, on the other hand, it is a 

 highly developed plant differentiated into stem, leaf, and true root, 

 and bearing the sporangia on its leaves. The MODIFICATION OF THE 

 s IK mi is very slight in Filicmw. The first leaves of the embryo 

 ;m- very simple in form (Fig. 205), but after a certain age all the 

 leaves which arise are essentially alike. The fertile leaves do not 



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