Benedict: Revision of the genus Vittaria 397 



Necker retains Pteris to include, as he writes, "frondes compositae." 

 In Oetosis, however, the leaves are "simplices," and it is reasonable 

 to suppose that he meant to include under this name all the 

 Linnaean species of Pteris with simple leaves. In the 1753 Species 

 Plantarum there are four of these, but by 1767 two others had 

 been added, and this is also the number in Murray's edition of the 

 Systema Naturae of 1784. This fact seems to have been over- 

 looked by Dr. Greene, but it was noted by Kuntze, who in at- 

 tempting to validate Oetosis, selected as type of the genus the 

 first species named in the later Linnaean works, i. e. Pteris pilo- 

 selloides L., which, however, was not among the four known to 

 Linnaeus in 1753. Thi would identify the genus with a group 

 of the tribe Polypodieae, now known either as Drymoglossum 

 Presl, or perhaps more properly as Pteropsis Desvaux. 



It is probably unnecessary to pursue further the ignis fatuus 

 of a type for Oetosis, but it may be stated with certainty, as addi- 

 tional confirmation of the invalidity of this name that Necker's 

 description does not, as was Dr. Greene's main contention, fit 

 Pteris lineata better than any other of the simple Pterides known 

 to Linnaeus. The specific phrase which he cited as diagnostic, 

 "lineae parallelae," may be applied as well to the Pteris pilosel- 

 loides of Linnaeus, but it is scarcely probable that Necker had 

 any thought of distinguishing generically between one species 

 which has sporangial lines exactly parallel as in Vittaria lineata, 

 and another in which the lines diverge from the parallel one or 

 two degrees as in Linnaeus's Pteris lanceolata and others. 



Subgenus Radiovittaria Benedict, Bull. Torrey Club 38: 166. 



191 



Stem radial, phyllotaxy polystichous, leaf-trace always single, 

 stem and petioles brown, owing to the highly developed collen- 

 chyma. Spores diplanate, paraphyses with cupuliform terminal 

 cells. 



The radial stem structure and leaf arrangement as well as the 

 specialized collenchyma (see Fig. 6) serve to separate the species 

 included from the other species of the genus, which also show a 

 much wider range of characters. 



In the key which follows, the species are arranged as nearly as 



