147 



Acrosticlium as outlined by Linnaeus contained ferns having the 

 sporangia scattered in a layer over the under surface of the leaf, 

 and in separating the members of this group, he did not distin- 

 guish those which have distinct sori when young which later be- 

 come confluent. Without these his genus formed a sufficiently 

 unnatural group, containing as it did species of Sc/iisaea, Da- 

 naea, Stenochlaena, Ceratopteris, Hymenodium, and Todea in 

 addition to Acrostichum aureum, the type of the genus, and to 

 these were added Poly podium poly podioides, Asplenium platyneuron, 

 Asplenium septentrionale, Lorinseria areolata, Woodsia Ilvensis 

 and Dryopteris Thelyptcris by way of variety, together with 

 species of Notholaena, Trismeria, and Ceroptcris. Should anyone 

 suppose that the fern system of the miscalled " Father of Botany " 

 was anything but crude even for the time at which it was pro- 

 posed, the contemplation of this array of misfits should serve as 

 convincing evidence to the contrary. 



The genus Pteris in the Species Plantarum is a little better 

 although it contained members of the genera Vittaria, Notlio- 

 laena, Gymnopteris, Dryopteris, Pteridium, Dicrano pteris, and 

 Pellaea as now recognized, in addition to species which still help 

 to make up the genus Pteris with a single continuous marginal 

 indusium and free veins. Asplenium was a somewhat more 

 natural aggregate commencing with the single-leaved species of 

 Camptosorus, Phyllitis, and Tliamuopteris, and passing on to 

 Ceterach and the more divided members of the genus Asplenium, 

 now distributed among several genera but, with perhaps a single 

 exception, all members of the tribe Asplenieae as now recognized. 

 A serious relapse occurred again in Polypodium which included 

 all the species with rounded sori whether indusiate or not ; be- 

 sides representatives of the various genera still included under 

 Polypodium in certain quarters, Polypodium of Species Plantarum 

 contained species of Tectaria, Polystichum, and Phegopteris to- 

 gether with Asplenium font anum, A. filix-foemina, several species 

 of Dryopteris, including D. filix-mas, D. cristata, D. Novebora- 

 censis, and D. marginalis, Filix bulbifera and F. fragilis, Cibotium 

 Barometz, Cyathea arborca, Hemitelia horrida, AlsopJnla aspera, 

 and others equally diverse in character. 



