fa 
BENEDICT: GENERA OF THE FERN TRIBE VITTARIEAE 17k 
development, generally shows as wide a divergence from the sim- 
ple type as do the species of Polytaenium. Whatever its proper 
rank or name, the significance of P. quadriseriatum is the same, 
and it serves to connect the pluriseriate venation pattern of 
Polytaenium, Ananthacorus, and Anetium with that of Vittaria. 
The venation of Polytaenium is illustrated by figures of several 
species (PLATE 6, FIG. I; PLATE 7, FIG. 3-6, 8). By reference to 
these figures, it may be noted that the areolae decrease in size 
from the midvein toward the margin. In the narrow-leaved 
species, which have all the areolae parallel to the midvein, this 
decrease takes approximately the ratio of 1:4: 4%, the length 
of a costal areola being taken as the unit. In the broader-leaved 
species, only the costal areolae are parallel to the midvein, and 
the divergence of the others increases their proportionate length, 
although a steady decrease in size toward the margin is still the 
rule. In the broadest species, P. Jenmani, as also in Anetium, 
the divergence in the outermost areolae approaches an angle of 
go°. The other species furnish all gradations between this broad- 
est type and that of the narrowest species, P. quadriseriatum. 
The external stem characters are practically alike for all the 
genera, the only difference being in the size. The scales are of the 
general clathrate type and are alike except for some slight varia- 
tions in size, shape, and margin. The spores are triplanate in 
nine out of the ten species here recognized, and these same nine 
species lack paraphyses. 
One species, Polytaenium ensiforme, has both diplanate spores 
and capitate pyriform paraphyses. It was recognized in my earlier 
paper as a distinct subgenus, Scoliosorus Moore, but perhaps this 
distinction is unwarranted. 
Another subgenus based on a soral difference, namely, Poly- 
taenium Desv., was also recognized at that time, including a single 
species, “ Antrophyum” lineatum. If this were worth maintaining, 
Polytaenium quadriseriatum would now have to be included, the 
two species together to constitute the subgenus Eupolytaenium, 
but there does not appear to be any necessity for such separation. 
The sporangia are borne in lines of greater or less extent, in 
some species always simple, in others branching and, in still others 
incompletely anastomosing. In most of the species of Polytaentum 
