POLYPODIACE^. 339 



tinguis)ial»le from it l)y tlie less scaly rhacliis and mucli obtiiser am'iclcs (.)f the 



pi 11 1103. 



Group of Folystichum tripteron Pr. 



Sjjecies Ijclouging to tliis grouii having simply piunate froncls with piuuate 

 lowest pinna3, which are louger than the others and are arranged liorizoutally, 

 were previously two in all ; oue is the Japauese species, P. tripteron Pr. aud 

 the other, the Forniosan, P. HancochU Diels. lii my last excursiou to Formosa, 

 I paid special atteutiou to this group of ferus and found several new species 

 which are very similar iu appearauce yet separable iu details. Of all the species, 

 P. tripteron Pr. is the most easily distinguishable from the others iu having 

 narrowest pinufB with by far the sharpcst teeth, in the thinuest texture aud iu 

 the cellular striicture of the scales. Polysticlmm longistipes Hayata aud P. 

 Sancockii Diels are separable from the otlier species hy the very long stijies 

 which nearly eqiial the fronds in length. P. simplicipinnum Hayata aud P. 

 yceyamense ]\Iakino differ from the others by the lowest pinuiB which are 

 nearly the same as the other pinnaj or slighly longer and scarcely pinnate. 

 As can be considered from the foUowing key, the distinctiou betweeu each two 

 of the species can not be very clearly giveu in verbal expressiou and the 

 ,difference itself is really very small, so that even to acciuute observers it woiild 

 be difficiilt to recognize the species proposed by me. I myself am jiretty 

 siire that many botanists will be apt to render my s^iecies to varieties of the 

 oldest species Polystichum tripteron Pr. As it is a very difficiilt task and 

 depends to a greater extent iipon personal opinious, to decide whether they 

 should stand each distinct or should be regarded as varieties of some oue 

 species, I shall at preseut leave the questiou eutirely to the readers. 



Key to the species of the group represented by Polystichum tripteron Pb- 



A. The lowest pinna3 are very miich longer thau the nthers aud are usually 

 once more i^innate. 



a. Fronds much longer thau the stipes. 



«. pinufe inore than 2cm, long, more or less reciirved after /^^-form, 

 more sharply toothed. Polystichmn tripteron Pr. 



