REVIEWS INTRODUCTION TO CRYPTOGAMIC BOTANY. 345 



G-ymnogens, Endogens, and Acrogens, seem to us well marked 

 classes, the two former among Pheenogams, the latter among Crypto- 

 gams ; but if there be any real resemblance between Palm Cyca- 

 daceae and Perns indicating an osculant point, we must not be 

 deterred from recognizing this fact by fear of impairing the distinct- 

 ness of the line of demarcation. But we leave this subject to lay 

 before our readers the passage from Mr. Berkeley's argument on the 

 importance of cryptogamic studies : " Another excellent inducement 

 to the study of cryptogams is the fact that so many of the diseases, 

 both of plants and animals, arise from their presence. The species 

 which affect animals are probably few in number, and for the most 

 part of common kinds, possessing great powers of ubiquity, and 

 therefore able to establish themselves on what, from the very nature 

 of things, cannot be their natural habitat. Though great attention 

 has been paid to the study of such cryptogams as infest man, and 

 other animals, they have seldom been studied by competent persons, 

 possessed of an accurate knowledge of species, much less of a power 

 of appreciating the changes which may take place in the same 

 species, according to varying outward circumstances. Those who 

 have recorded their occurrence, or have given figures illustrative of 

 their aspect and structure, accompanied by distinctive characters, 

 have often been physicians, better versed in anatomy and microscopy 

 than in cryptogamic botany, and often unable to distinguish a mould 

 from an alga. The parasites of the vegetable world are much more 

 numerous, and are clearly autonomous ; and, as some of them pro- 

 duce great ravages on those plants which most subserve the use of 

 man, their study is of immense economical value, apart from other 

 less utilitarian considerations. Till these parasites are accurately 

 distinguished from each other, all attempts at remedy must be- 

 empirical ; and thus, in the case of the diseases which afifect the hop, 

 no efficient remedy was even attempted till the nature of the two 

 principal diseases with which the plant is affected, known under a 

 multitude of names, was accurately ascertained." 



The remaining portion of the volume is occupied by details 

 respecting particular orders beginning with the lowest Thallogens, 

 and terminating with the ferns, the highest in rank of cryptogamic 

 plants. Instead of at once dividing Thallogens according to Lindley's 

 plan into the Algal, Fungal, and Lichenal alliances, Mr. Berkeley 

 regards the two latter as more closely connected, and' judges it neces- 

 sary, contrary we think to convenience and practical utility, to put 



VOL. in. X 



