Die Farnkräuter der Erde

Abstract

SINCE the publication of Baker's “Synopsis Filicum” in 1873 (Dr. Christ makes no mention of John Smith's “History of Ferns,” 1877) no complete systematic account of the ferns has appeared, so that there is room for a work which embodies the more modern discoveries in this subdivision of plants. During this interval, Dr. Christ says a number of new species have become known, and, owing to the researches of G. Mettenius into the general structure of this subdivision, additional materials are to hand for the elaboration of a more natural arrangement. He believes that the older authors, including Hooker, too rigidly limited themselves to the consideration of the sorus and indusium for purposes of classification. Influenced by these reflections he has been led to change the arrangement adopted in the “Synopsis Filicum,” in several cases, for what he regards as a more natural grouping. His view of the matter is, however, sometimes open to doubt. The position he assigns to the genus Loxsoma may be taken as an example of one of such alterations. He transfers it from the Hymenophyllaceæ to the Polypodiaceæ, apparently because its leaves have several layers of cells and are furnished with stomata. On the other hand, its sorus and indusium resemble those found in the Hymenophyllaceæ. An alteration like this may be defended or assailed according to the personal feeling of each systematist, and its criticism will depend on what morphological value each individual places on the various diagnostic characteristics. But it appears that the structure of the leaves, taken alone, would often be misleading. The leaves of a few of the Hymenophyllaceæ are several layers thick; while in the Osmundaceæ—a group, for the most part, possessed of stout leaves—Leptopteris has delicate and filmy leaves without stomata. The existence of the fossil Palæopteris hibernica, which had leaves resembling Loxsoma, but in other respects belonging to the Hymenophyllaceæ, renders the connection of the latter genus to that class of ferns more probable.

Die Farnkräuter der Erde.

By Dr. H. Christ. Pp. viii + 388; with 291 figures. (Jena: Gustav Fischer, 1897.)