CONTRinUTlONS TO THK FF.ORA OF IOWA. 65 



giving, on the whole, the best uniform classification, in accordance with 

 recent views, that is accessible to all. It will be necessary, however, 

 to reverse the order of the book, and pass from the higher to the lower 

 forms, so as to make the added part of the catalogue continuous with 

 the portion already published. The i)articular arrangement to be ob- 

 served for species will be anno, meed for each order when the first list 

 under it is published. 



The present contribution contains all the i)teridophytes or vascular 

 cryptogams at present known to occur in the State. The orders are 

 arranged according to Bessey's Botany, and the genera and species 

 according to Underwood's "Our Native Ferns and their Allies," a most 

 vahiable work.* The list is considered (]uite complete, being much 

 larger than has before been accredited to the State. The following 

 named ferns, however, may (juite confidently be ex[)ected to occur 

 within our borders, and the attention of collectors is s[)ecially directed 

 to their detection : Cheilauthcs vestita, Aspleninm cbenciim, A. Tric/io- 

 maiies, Phegoptcris Dryoptcris, Aspidium Noveboraceiisc^ A. filix-iiias, 

 A. marginale, A. cristati/in, A. cristatum, var. Cliiitonianuin. 



The present list only covers, geographically, about one-half the State. 

 If a nearly straight fine be drawn from the northwest to the southeast 

 corner, it will pretty accurately sejiarate the eastern portion, the pteri- 

 dophytic flora of which is (juite well known, from the western portion, 

 from which no si:)ecimens have yet been received. The northwestern 

 part of the State consists almost wholly of treeless prairies, with few 

 localities suitable to the growth of ferns and allied plants. What the 

 rest of the western part of the State aftbrds must be determined by 

 future explorations. The State as a whole is not a favored one for such 

 plants. They are most numerous, in both species and individuals, 

 along the Mississippi River, and become fewer as we jjass westward. 

 The peculiarity of the flora is well indicated in the sparseness of lyco- 

 pods and selaginellas, but one locality being known for the only species 

 oi Lycopodimn yet reported, and only two localities with few individuals 

 for the single Selaginella. 



Much credit is due the several collectors for the trouble they have 

 taken to obtain and forward specimens. Those communicating mate- 

 rial for the present contribution are as follows : R. I. Cratty, of Arm- 

 strong, Emmet county; E. W. Holway, of Decorah; John Leiberg, 

 late of Mankato, Minnesota; Prof. C. E. Bessey, of Ames; Prof, and 



*To be obtained of the author. Prof. L. M. Uncierwood, Syracuse, N. V.; price, $1.25. 

 [Proc. D. a. N. S., Vol. IV.] 9 [May ^, 1884.] 



