﻿Maxon: Polypodium marginellum and its allies 225 



of a slender band of rigid lustrous ebeneous sclerotic tissue, gla- 

 bra te; veins numerous, free, very oblique, arising at an angle of 

 about 20°, the sterile ones simple, the fertile ones essentially so, the 

 sori (usually confined to the apical half of the lamina) distinctly 

 inframedial in attachment, seated upon an elliptical translucent 

 receptacle lying upon the distal side of the vein and scarcely di- 

 vergent from it, relatively large, crowded against the costa, the 

 two lines of sori more or less confluent at maturity. Leaf tissue 

 glabrous, rigidly herbaceous, translucent, dark green above, paler 

 beneath ; costa slender, dark brown, elevated beneath ; veins readily 

 seen beneath without transmitted light. 



Type in the U. S. National Herbarium, no. 370659, collected 

 upon the island of St. Helena, 1885, by W. H. King. 



Reported commonly from St. Helena, as P. marginellum, but in 

 the National Herbarium represented only by the specimens of Mr. 

 King. It is the smallest member of the group and readily recog- 

 nizable as distinct from its American relatives in both gross and 

 minute characters. This or a very closely related form is mentioned 

 from Guinea by Link,* as P. marginellum. There is also a single 

 Canary Island specimen, collected long ago by L. von Buch, which 

 may possibly be the same. This was first referred to the West 

 Indian P. gramineum {Grammitis linearis Swartz), but was after- 

 ward described as a new species, Grammitis quaerenda BoUe.f 

 Still later it was discussed by Kuhn,t who mentions the "char- 

 acteristic deep black margin" and refers it to P. marginellum, 

 adding that it is identical with specimens collected on St. Helena 

 by d'Urville and apparently misidentified by Mettenius as P. gram- 

 ineum. Kuhn's unsupported statement as to the identity of the 

 Canary Island and St. Helena plants does not, however, seem at all 

 conclusive, in view of the several very obvious errors of fact which 

 occur elsewhere in his paper and considering also the circumstance 

 that under the name P. marginellum, with a single variety, he 

 lists a total of only six specimens (apparently all that were known 

 to him) which certainly pertain to no less than three species. It 

 seems proper to describe the St. Helena plant as new, for it is not 

 at all improbable that the Canary Island form, if eventually found 

 in sufficient quantity for study, will prove to be a distinct species. 



t Zeitschr. Allgem. Erdk. II. 14: 324. 1863. 

 t Oesterr, Bot. Zeitschr. 16: 70. 1866. 



