ON WOODSIA, mo

A NEW GENUS OF FERNS.

��There is perhaps no tribe of cryptogamous plants which since the time of Linnaeus has received greater additions to its number of species, or more considerable improvements in its systematic arrangement, than the Filices ; and certainly no botanist has so essentially con- tributed to these improvements as the President of this Society ; whose ingenious Essay on Dorsiferous Ferns may justly be considered as the groundwork of the more com- plete dissertations of Professors Swartz and Bernhardi, which have appeared since its publication. 1

Linnaeus, in his latest work, the 13th edition of the Sgs- tema Vegetabilium, enumerates scarcely more than 200 Ferns, which he referred to twelve genera : while the Species Plantarum of the late Professor Willdenow contains upwards of a thousand plants of the same order, arranged under forty-three genera. It is however remarkable, that of this vast number of species nearly one half belong to four of the Linnean genera, namely, Poly podium, Acrosti- chum, Aspleniam, and Pteris, all of which were first pro- posed by Ray in his Metliodus Plantarum Emendata, pub- lished in 1703; without names, indeed, but with cha-cm meters nearly similar to those of Linnaeus.

It appears, therefore, that the arrangement of Ferns at present universally followed is not wholly new : and that it has not attained such a degree of perfection as to super-

1 An. 1793, in Mem. de VAcademie Royale des Sciences de Turin, vol. v, p. 401.

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