204 BOTANY. 



not all thallus plants, nor are all the thallus plants found in the Thal- 

 lophyta ; on the other haud, the Cormophytes are not all plants with 

 trunks or stems. 



(6) We often, however, retain in our present classification some of 

 the groups founded originally in this erroneous way, and even some- 

 times retain their old names. For example, the group Phanerogamia 

 includes now the same plants it did when its exceedingly inapplicable 

 name (Phanerogamia, from QavepoS, open to sight, and ya^oS, marriage) 

 was applied to it ; but it now rests upon a more scientific basis. The 

 name is now unmeaning, and refers to no character or set of characters 

 now used to designate the group ; and, more than this, its etymological 

 signification is actually directly opposite to the facts as now known. 

 The term Cryptogamia (/cpiwrof, hidden, and ya.fj.os, marriage) no longer 

 exists in a scientific sense, as it is no longer the name of a group of 

 plants ; not only has the term now no meaning (for the plants it refers 

 to have a fertilization which is far less " hidden " than in the so-called 

 Phanerogams), but the plants it formerly designated by a negative 

 character are now known by positive characters to belong to several 

 groups. We may still use the word Cryptogam in speaking of the 

 members of certain groups of plants, just as in zoology we frequently 

 make use of the word Invertebrate ; but in neither case are the terms 

 the names of natural groups, or of natural assemblages of groups. It 

 is convenient to retain them as popular names of certain artificial as- 

 semblages of groups. 



(c) The term Thallophyta is to be placed in the same category. It is 

 still used to designate a great assemblage of the lower plants, but the 

 original meaning of the term is lost, and the limits of the group to 

 which it was applied have been somewhat changed, while the plants 

 composing it have undergone an entirely new distribution into new 

 groups. Nevertheless, it is convenient to retain the term, although in 

 this, as in the previous cases, care must be taken not to suppose that 

 when used it designates more than an artificial assemblage of natural 

 groups of plants. 



(d) The importance of the study of the individual development of 

 plants can hardly be overestimated. What Embryology has done for 

 zoological, it doubtless can do for botanical classification. It is already 

 bearing fruit ; the recent advances in the classification of the algae and 

 fungi are due to a study of the whole life of the individual. In the 

 fungi the long list of spurious families and genera, and the yet longer 

 one of spurious species, bear witness against the system of classification 

 under which they came into existence. 



(e) There is another reason for studying closely the life-history of the 

 individual, which is that it throws some light upon the difficult ques- 

 tions relating to the ancestry of plants. The life-history of the indi- 

 vidual appears to bear much resemblance to the life-history of the 

 species ; and while no doubt it would be unsafe in any particular case 



