ON THE HIGHER CRYPTOGAMOUS PLANTS. 103 



drawing up a summary of the state of knowledge of the repi-odaction of the 

 higher flowerless plants, by the importance of the discoveries which have re- 

 cently been made in this department, tending completely to change the general 

 views which have hitherto been entertained by most botanists as to the extent 

 to which sexuality exists in the vegetable kingdom, and in connexion with 

 other new facts relating to the Thallopbytes, to indicate that the existence 

 of two sexes is universal. 



Under the name of the higher Flowerless Plants, I include all those classes 

 which are distinguished on the one hand from the Thallophytes or Cellular 

 plants by the presence of a distinct stem bearing leaves, and on the other 

 from the Monocotyledons and Dicotyledons by the absence of the organs con- 

 stituting a true flower ; they are, the Hepaticae, Musci, Equisetaceae, Filices, 

 Lycopodiaceae, Isoetacese, and Marsileaceae or Rhizocarpese. 



On no subject has more discussion been maintained than on the existence 

 of sexes among the Cryptogamous families. The discovery of the two kinds 

 of organs, the antheridia and jiistillidia, in the Mosses and Hepaticae, and of 

 the peculiar organs containing analogous spiral filaments in the Characeee, were 

 for a long time the chief facts brought forward by those who supported the 

 sexual hypothesis ; and in the endeavour to carry out the view into the other 

 tribes, a similar nature to that of the antheridia was attributed to most varied 

 structures in the Ferns and other plants. These attempts to find distinct 

 sexual organs were in some instances pursued with so little judgement, that 

 the opinion had of late years fallen in some degree into discredit, and two 

 circumstances contributed still further to strengthen the doubts which were 

 entertained. The first was the exact analogy, pointed out by Prof, von 

 Mohl, between the mode of development of the spores of the Cryptogamia 

 and the pollen-grains of the flowering plants, which interfered very import- 

 antly to prevent any comparison between the sporangia and ovaries, and 

 apparently determined the analogy of the former to be with anthers. The 

 second was the discovery by Prof. Nageli, of organs producing spiral fila- 

 ments, therefore analogous to the antheridia of the Mosses, on the germ 

 frond, Qv pro-emhyo developed from the spores of the Ferns. 



At the same time, the facts observed in Pilularia were altogether equivo- 

 cal. Mr. Valentine* traced the development of the larger spores, exhibiting 

 in germination an evident analogy to ovules, from cells closely resembling 

 the parent-cells of pollen and spores ; while Prof. Schleiden stated that he 

 had observed a fertilization of these supposed ovules by the smaller spores 

 resembling pollen-grains, and thus seemed to remove the ground for attri- 

 buting a fertilizing influence to the spiral filaments contained in the so-called 

 antheridia of the Cryptogams. 



In this state the question remained until 1848, when Count Suminski |- 

 published his observations on the germination of Ferns, showing that the 

 researches of Nageli had been imperfect, and that two kinds of organs are 

 produced upon the pro-embryo of the Ferns, one kind analogous to the 

 antheridia, and the other to the pistillidia of Mosses ; from the latter of 

 which the true Fern stem is produced, like the seta and capsule from the 

 same organ in the Mosses ; further stating that he had actually observed a 

 process of fertilization. Soon after this M. G. Thuretij; discovered anthe- 

 ridia like those of the Ferns in the Equisetaceae ; Niigeii § had previously 



* Linnean Transactions, vol. xvii. 



t Entwickelungsgeschicbte der Farreukrauter. Berlin, 1848. 



X Ann. des Sci. Nat. ser. 3, vol. xi. 1849. 



§ Zeitscbrift fiir Wiss. Botanik, Heft 3. Zivrich, 1846. 



