46 INTRODUCTION. 



of Count Suminski upon the development of the Ferns (1848), 

 that the way was first opened to the i-ight comprehension 

 of the reproductive process in that group ; and the doctrine 

 of the fertilizing powers of the "antherozoids," once estahlished 

 in a single case, was soon proved to apply equally well to 

 many others. Not a year has since elapsed, without the pro- 

 duction of new evidence of the like sexuality in the several 

 groups of the Cryptogamic series ; this having heen especially 

 furnished by Hofmeister in regard to the higher types, by Thuret 

 and Decaisne as to the marine Algse, and by Tulasne with re- 

 spect to Lichens and Fungi ; and the doctrine may now be con- 

 sidered as established beyond the reach of cavil from any but 

 those, who, having early committed themselves dogmatically to 

 the negative opinion, have not the candor to allow due weight 

 to the evidence on the aiBrmative side. With the study of the 

 Reproduction of these plants, that of the history of their Develop- 

 ment has naturally been connected ; and some of the facts already 

 brought to light, especially by the study of certain forms of Fun- 

 gous vegetation, demonstrate the extreme importance of this 

 inquiry in settling the foundations of Classification. For whereas 

 the arrangement of Fungi, as of other Plants, has been based 

 upon the characters furnished by their fructification, these chai'ac- 

 ters have been found by Tulasne to be frequently subject to vai'ia- 

 tions so wide, that one and the same individual shall present two 

 or more kinds of fructification, such as had been previously con- 

 sidered to be peculiar to distinct orders. In this department of 

 study, which has been scarcely at all cultivated by Microscopists 

 of our own country, there is a peculiarly wide field for careful' 

 and painstaking research, and a sure prospect of an ample har- 

 vest of discovery. (On the subjects of the two preceding para- 

 graphs, see Chap. VII.) 



Although it has been in Cryptogamic Botany, that the zealous 

 pui-suit of Microscopic inquiry has been most conducive to scien- 

 tific progress, yet the attention of Vegetable Anatomists and 

 Physiologists has been also largely and productively directed to 

 the minute structure and life-history of Flowering Plants. For 

 although some of the general features of that structure had been 

 made out by the earlier observers, and successive additions had 

 been made to the knowledge of them, previously to the new era 

 to which reference has so often been made, yet all this knowledge 

 required to be completed and m^de exact, by a more refined ex- 

 amination of the Elementary Tissues than was before possible ; 

 and little was certainly known in regard to those processes of 

 gro-wth, development, and reproduction, in which their activity 

 as living organisms consists. All the researches which have 

 been made upon this point, tend most completely to bear out 

 the general doctrine so clearly set forth by Schleiden, as to the 

 independent vitality of each integral part of the fabric ; and 

 among the most curious results of the inquiries which have been 



