IXTRODUCTIOX. V 



In tliis rospect, nur plant is justly referablc to Disporojjsis. Yet, it is 

 uot imjiossiblo tliat tlie " corona " is quite a different thing from wliat I liave 

 imagineil, aml that our plant is of a generic cliaracter entirely different from 

 tliat of Hance's genus. Had the author given hut a sketch, however rough, 

 tiiere could have arisen no sucli confusion. 



Otlier plant, witli respect to which I desire to ask my readers' assistance 

 in determining its proper genus, is a species of Pohjpodiiim, ealled P. tcrceolare. 

 Tiie fern is undouhtedly a species referable to Prosaptia wliicli, according to 

 tlie leading pteridologists, is considered to be a subgenus of DavaUia. Yet, 

 ([uite contrary to current opinion, I have referred it to Polypodium. As this 

 niatter rerpiircs a full explanation ton long to be treated here in tliis 

 Introduction, I shall give niy reasons as iierfectly as possiblc in pp. .326-332, 

 in tlie note on Pohjpodiura urceolarc. 



In the present volume, I give floral sketches of some of luy specics ah-eady 

 descriljcd, as I desire to present a clear conception of my species to any one 

 who may examine tliera to see whether they shouhl lie recognized as genuine 

 new species or be reduccd to known si)ecies ; but tlic original deseriiition in 

 each case is not repeated, as the space is hei-e more limited tlian it was in the 

 preceding volume. >Sonie of the figures contained in tlie section oii plianero- 

 gamous plants are reproduced from my field notes (h-awn from tlie living 

 inaterial. Tliough tliey may be rough in appearance, tliey arc more trustworthy 

 in the exactness of the outline, than those drawn from dried specimens. Almost 

 all woodcuts given in tlie cryptogamous sections are reprodueed from my own 

 sketclies which were drawn with the aid of " Zeichenaiiparat nacli Abbe." 

 In sucli reproductions, tlie original sketches are usually reduced to \ size. 

 Great care has been taken in sliowing tlie venation of fronds and the cellular 

 structure of tlie scales. 



I avail myself of tliis oiiiiortunity to tendcr my liearty tlianks to the 



