INTRODUCTION. V 



specimens should supplement their original descriptions with perfect materials 

 as soon as possible. 



As this volume is principally devoted to studies of the Or chide se and 

 Pteridophyta, a few remarks on the classification upon which the two 

 families is based will not be out of place. In working up my collections of 

 orchids, I have principally followed BENTHAM and HOOKER, sometimes LINDLEY, 

 KING and PANTUNG, and PFITZER. As to the classification of Monandrse- 

 Acrotonse, many authorities do not agree. *PFITZER'S system which, taking 

 into account whether the inflorescence is terminal or lateral, distinguishes 

 Acranthae and Pleuranthse, or, on the basis of the vernation of the 

 leaves being either convolutive or duplicative, makes many divisions in the 

 above named tribes, proved to be impracticable in working up my materials. 

 Moreover, I have found many doubtful cases, so far as inflorescence being 

 terminal or lateral is concerned, and there are even more cases in which it 

 is impossible to determine whether the vernation of the leaves is duplicative 

 or convolutive. KING and PANTLING'S Orchids of the Sikkim Himalayas in 

 Ann. Hoy. Bot. Gard. Calc. Vol. VHI. and several other illustrations given 

 in the same Annals have been very useful to me in identifying and com- 

 paring my collections of orchids. 



As to ferns and especially to the genus, Dryopteris, I have followed 

 C. CHRISTENSEN'S system in his Index Filicum. His classification of the 

 subgenera of the genus** is based principally on the presence or absence of 

 hairs and on their structures. This newly founded system is certainly one of 

 the most natural arrangements and has proved to be easily applicable to 

 Formosan ferns. But, as far as Japanese and Formosau species are con- 

 cerned, there are a few cases in which I can scarcely agree with the author. 

 Some species which are taken by him as types of a subgenus do not show 

 the characters of the same subgenus, after the delimitation of the latter as 

 stated by him. For example, Dryopteris Miqueliana (Max.) C. CH. which is 

 taken as one of types of the subgenus, Eudryopteris, which after CHRISTEN- 



* PFITZEB, E. Orchidaceai in ENGLEK u. PRANTL, nat. Pfl. fam. II-6, p. 76. 

 ** CHRISTENSEN, C. On a natural classification of the species of Dryopteris, pp. 74-76, and a 

 monograph of the genus Dryopteris part-1, pp. 61-63. 



