Ill] CRITICAL EXAMINATION OF CRITERIA NECESSARY 65 



considered, and in each case the relatively primitive will be distinguished 

 from the relatively advanced. Thus the way will be prepared for using that 

 criterion, in conjunction with others, for the purpose of phyletic seriation 

 of the Ferns. If upon this wide basis, and subject to the palaeontological 

 check, the comparisons and arguments are correctly pursued, the result 

 should provide a trustworthy classification of this large and varied class of 

 plants. It should in fact reflect the probable course which the evolutionary 

 history of the Filicales has actually pursued. Incidentally a wider apprecia- 

 tion of the plants themselves will have been acquired, and the basis found 

 for sane views as to the evolutionary origin of those parts which are seen 

 highly elaborated in their more advanced types. 



BIBLIOGRAPHY FOR CHAPTER III 



23. Christensen. Index Filicum. 1906. 



24. Engler & Prantl. Natiirl. Pflanzenfam. i, 4. 1902. 



25. Christ. Die Famkrauter der Erde. 1897. 



26. Hooker. Species Filicum. 1846 — 1864. 



27. Hooker & Baker. Synopsis Filicum. 1868. 



28. BoMMER. Monographie de la Classe des Fougeres. Bull, de la Soc. Roy. de Bot. 

 de Belgique. Tome v, No. 3. A useful summary is here given of the Classifications 

 of Ferns devised by various authors up to 1867. 



29. Mettenius. Filices Horti Lipsiensis. 1856. 



30. Prantl. System der Fame. Arbeiten a. d. Konigl. Bot. Gart. zu Breslau. 1892. 

 Here a complete list of the author's own writings on the Classification of Ferns up to 

 that date is given. 



31. Naegeli. Zeitschr. f. vviss. Bot. iii. 1845. 



32. Bower. Ann. of Bot. iii, p. 305. 1889. 



33. Campbell. Bot. Gaz. xv, p. i. 1890. 



34. Bower. Ann. of Bot. v, p. 109. 1891. 



35. Von Goebel. Bot. Zeit. 1881, p. 681, etc. 



