— 21 — 



fern has been placed in one genus by one author and in another 

 genus by a second author, The fact is that if a person looks over 

 the " Synopsis Filicum" with a view to investigate this question, 

 he will be surprised at the number of Nephrodium species of 

 which it is said that the involucre is "fugacious," or "very 

 fugacious," which means that the involucre is never seen on 

 them ; or that the capsules are entirely "naked." Any one who 

 has had occasion to study long suites of specimens in an her- 

 barium knows to his vexation that this fugacious character is no 

 mere figure of speech. 



Thus we have at the present time two genera taking the 

 place of three previous ones, and under Dryopteris a still greater 

 aggregation of species than before. Meanwhile new species of 

 this genus are being published from time to time, and its number 

 is being increased and becoming more and more unwieldy. The 

 last edition of "Synopsis Filicum" described 3^0 species of 

 A spidium and Nephrodium, while Baker's "New Ferns" gives 

 166 more for the two species. This makes 526 species for Dryop- 

 teris ; but as Baker's book was published in 1892, the probability 

 is that the genus by this time numbers 550 species. This is ex- 

 clusive of a large number of forms which may be varieties, or 

 may prove to be good species. 



It may be urged that the genus Polypodium, after taking out 

 Phegopteris, Goniopteris and Dictyopteris, will still aggregate 

 about the same number as I have calculated for Dryopteris. 

 That is correct ; but it must be remembered that the Eremobryoid 

 Polypodia are divided into five very distinct sub-genera by their 

 venation, which is so distinct and constant as almost, if not 

 fully to warrant the establishment of genera upon their 

 different forms. In Dryopteris this is not the case. Leaving 

 out of sight for the present the sub-genera given in "Synopsis 

 Filicum" as Eu- A spidium and Sagenia, there remain only two 

 distinctions in the way of venation to divide the entire mass, viz., 

 the free-veined and the pinnate-veined, with opposite groups of 

 veins more or less united. Polypodium, therefore, stands on an 

 entirely different footing, with regard to its sub-genera, from the 

 equally large genus Drypoteris, because the former has such dis- 

 tinctive zones of venation. 



I now come to the main purpose for which this paper is writ- 

 ten, viz., some suggestions as to the rearrangement of the 600 to 

 70u species about which we have already been talking. It is per- 



