CLASSIFICATION OF PLANTS. 177 



ever, we may consider as possibly expressing only our igno- 

 rance. This class comprises the different families confounded 

 under the names of algce, fungi, and lichens. The characters 

 common to all these vegetables are as follows: they are 

 entirely formed of cellular tissue, or rather of interlacing 

 tubular filaments, without vessels properly so called ; they 

 never present true leaves, and their organs of reproduction 

 consist only of very fine seedlings, which appear to develope 

 themselves without fecundation, and are immediately inclosed 

 in membranous conceptacles analogous to the filaments of 

 that tissue which composes the whole of the plant. The 

 only fossil plants of this class known are some confervce, with 

 several algcs. 



" The second class, that of the cellular cryptogamice, com- 

 prises the two families of hepaticce, or liverworts, and musci, 

 or mosses ; their organs of vegetation, although solely com- 

 posed of cellular tissue, offer, in most cases, leaves well 

 characterised by their form, their structure, and by the fact 

 that they are similar to those of the most perfect vegetables. 

 Their organs of reproduction present a more complicated 

 structure ; there are sexual organs very distinct, which have 

 been perfectly described by Hedwig ; the seedlings are con- 

 tained in conceptacles of very complex organisation. One 

 fossil plant only is known as appertaining to this class. 



" The third class, that of the vascular cryptogamicB, includes 

 those vegetables, the more varied tissues of which almost 

 always include perfectly distinct vessels, and very frequently 

 spiral vessels or imperfect spiral vessels, while the leaves are 

 in -general very fully developed, and furnished with cortical 

 pores ; the stems, which are often large and arborescent, have 

 some analogy with those of monocotyledons ; and finally, the 

 organs of reproduction always appear to consist of two dis- 

 tinct sexes, which produce seedlings inclosed in conceptacles 

 of a somewhat complicated organisation. To this class belong 

 the equisetacea, the ferns, the lycopodiacece, the marsiliace<E, 

 and the characece. 



" In the fourth class, under the name oi phanerogamic 

 gymnosperms, we unite the two remarkable families of cycadecs 

 and conifer CB, which really cannot be confounded by associat- 

 ing them in either of the other classes with vegetables, from 

 which they are so distinct by the structure of their organs of 



