170 BENEDICT: GENERA OF THE FERN TRIBE VITTARIEAE 
confirmed: the results of the early external study and has also 
added some valuable facts to aid in species differentiation. 
One result of this further study has been the discovery of 
an undescribed species, which by reason of its venation and 
sporangial arrangement, serves as a connecting link with Vittaria 
and therefore deserves a name and description in this place. 
Polytaenium quadriseriatum sp. nov. 
Rootstock creeping, dorsiventral, the scales clathrate; leaves 
fasciculate, in two rows, firmly herbaceous, the petiole 3-angled, 
the blade linear, 12-20 cm. long, 3-5 mm. broad, narrowed very 
gradually and equally both ways, the apex acute; venation con- 
sisting of a midvein with two rows of areolae along each side; 
porangia in two long continuous deep grooves along the outer 
margins of the costal areolae, with sometimes additional short 
grooves along the outer areolae, the margins of the grooves pro- 
duced so as to meet, covering the sporangia when young; spores 
triplanate, no paraphyses. (PLATE 7, FIG. 8-10.) 
Type from Hayti, Nash & Taylor 1360, in Underwood Fern 
Herbarium, N. Y. Botanical Garden. 
The material on which this species is based was originally 
identified as Vittaria intramarginalis and was discovered during 
a study of that species. At first this identification was main- 
tained and the specimen was looked upon as an aberrant Vittaria, 
but further study has made it evident that it should not be 
retained in that genus and species, but is rather more nearly 
related to Polytaenium lineatum. It differs from the Vittaria in 
the 3-angled stipe, and in color, texture, venation, and soriation. 
It resembles P. lineatum in these respects, but differs from this 
species markedly in size and general appearance. If comparison 
is made between FIGURES 3 and 8 of PLATE 7, P. quadriseriatum 
will appear like P. lanceolatum in venation, but the soriation as 
figured for the latter species (FIG. 4) is entirely distinctive. P. 
quadriseriatum is particularly interesting, however, because of its 
position intermediate between the several species and two genera. 
Question may be raised as to the necessity of two genera since 
there are connecting species. This does not seem an adequate 
objection, in view of the wide difference between the two types, 
as shown in most species, and since Vittaria in its special line of 
