45o. PTERis. 359 



§ 1. EUPTERIS. c. C^omposilae. ". Bipinnatlfldae. 



a. Pinnae with a long, undivided terminal segment and mostly few, rarely 

 pectinate lateral ones near the base. 



b. Fronds dimorphous. (13) Pt. ensiformis. 



b.b. Fronds uniform or nearly so. 



c. Mains rachis winged by the decurrent bases of the pinnae. 



(14) Pt. serrulata. 

 c.c. Main rachis at best winged towards the apex. 



d. Pinnae divided on the lower side only. 



*■ Lowest pinnae with 2 large segments on the lower side. 



(15) Pt. sumatrana. 

 :)(..%. Lowest pinnae with more than 2, not very large seg- 

 ments on the lower side. (16) semipinnata. 



d.d. At least the lower pinnae divided on both sides. 



e. Pinnae generally with d — 6 segments on each side below 

 the long terminal one. 



f. Lower pinnae with the lateral segments short, close 

 or approximate. 



g. Secondary barren segments serrate' throughout. 

 h. Segments somewhat distant, decurrent. 



(17) Pt. dispar. 

 h.h. Segments close, not decurrent. 



(18) Pt. distans. 

 g.g. Secondary barren segments entire or at best 

 spinulosel serrate at or towards the apex. 



fo^ (19) Pt. heteromorpha. 



f.f. Lower pinnae with the segments long, distant. 



(20) PI. Dalhousiae. 

 e.e. Pinnae with numerous lateral segments on each side be- 

 low an often very long terminal one. 



(21) Pt. Beccariana. 

 a.a. Pinnae pectinato-pinnalisect throughout, with a rather short, rarely subcaudate 



point and ± many lateral segments on each side. 



1. Lateral pinnae few, i — 2 on each side below the terminal one. 



*. Veins indistinct. (22a) Pt. Grevilleana. 



*•)(«. Veins distinct. (226) Pt. pluricaudala. 



l.±. Lateral pinnae more numerous, at least 3 on each side. 



3. Fronds mostly under i25 c.M. long. 



