BENEDICT: GENERA OF THE FERN TRIBE VITTARIEAE 187 
inheritance of an unnecessary juvenile character in some of the 
ferns treated here. 
There is no evidence of the repetition of an unnecessary char- 
acter in the development of the twin net type of venation from 
that of Vittaria. It is impossible in this group to conceive of the 
higher type being developed from the simpler in any way but by 
the addition of secondary areolae along the previously formed 
costal areolae of the Vittaria stage. Similarly there is no evidence 
in the series found in Vittaria remota to show that any unnecessary 
stages were passed through here. 
But when the ontogeny of Vittaria remota is compared with 
that of V. intramarginalis a striking difference is to be noted. 
Both finally reach the same venation type, the only difference 
being that V. remota carries this type to a greater specialization 
than is found in the other Vittaria. In its ontogeny, however, 
V. intramarginalis passes through a free-veined stage like the 
mature condition of Hecistopteris, a stage which, as compared with 
the course of growth in V. remota, can hardly be considered other- 
wise than unnecessary. 
It has already been noted that Vittaria intramarginalis is to be 
considered lower in the evolutionary scale than V. remota, and this 
conclusion accords exactly with the differences in the ontogeny. 
Naturally the more primitive species would longer retain un- 
necessary ancestral characters. 
SUMMARY 
Several conclusions from the above study seem to deserve the 
emphasis of a repetition in the summary. 
1. The Vittarieae represent a well-defined, rather specialized 
natural group of ferns probably related to the Pterideae and to 
the Asplenieae. Seven genera are to be recognized, Monogramma 
Schk., Hecistopteris J. Sm., Vitiaria J. E. Sm., Polytaenium Desv., 
Ananthacorus Und. & Maxon, Anetium Splitg., and Antrophyum 
Kaulf. 
2. The genus Monogramma includes two species, M. dareicarpa 
Hook. and M. graminea (Poir.) Schk., which seem to possess the 
simplest leaf and stem structure known among vascular plants. 
3. The seven genera may be arranged according to their vena- 
