624 . PROCEEDINGS OF THE NATIONAL MVSEUM. vol.xxiii. 



of the undertaking itself and for considerable assistance in its early- 

 stages; to Prof. L. M. Underwood and Mr. George E. Davenport for 

 the completion or verification of many references, and especially to 

 the former for m&nj critical observations; to Mr. B. D. Gilbert for 

 courtesies extended, especially in the study of specimens in his excel- 

 lent private herbarium; to Mr, Frederick V. Coville, Mr. O. F. Cook, 

 Dr. J. N. Rose, and Mr. Charles Louis Pollard for numerous helpful 

 suggestions and criticisms; to Mr. Alvah A. Eaton for revising the 

 Isoetaceae and Equisetaceae; and to several others who have cour- 

 teously assisted by contributing specimens and data or by supplying 

 references otherwise unavailable. 



PTERIDOPHYTA Cohn. 

 Family I. OPHIOGLOSSACEAE Presl, Tent. Pterid. 10. 1836. 

 OPHIOGLOSSUM L. Sp. PI. 1062. 1753. 



Ophioglossum vulgatum L. Sp. PI. 10«>2. 1753. Adder's-tongue. 

 Quebec and Ontario, south to Florida. Also in California. 



Ophioglossum engelmanni Prantl, Jahrb. Kon. Bot. Gart. Berlin 3 : 318. 



jjj. l.f. 17. 1881. 



Virginia, Kentucky, Indiana, and ^lissouri, southwest to Louisiana, Texas, and 

 Arizona. 



Ophioglossum arenarium E. G. Britton, Bull. Torr. Club 24 : 555. pi. 



318. 2>l' S19. f. 3. 1897. 



Holly Beach, New Jersey. Rockingham County, New Hampshire {A. A. 

 Eaton) . 



Ophioglossum californicum Prantl, Jahrb. Kon. Bot. Gart. Berlin 3:315. 

 jjI. ;./. 11. 1881. 

 Near San Diego, California [Cleveland d- Parry; Pr ingle). 



Ophioglossum alaskanum E. G. Britton, Bull. Torr. Club 24 : 556. pi. 



319. f. o. 1897. 



Unalaska Lsland, Alaska (Turner). 



Ophioglossum pusillum Nutt. Gen. 2 : 248. 1818. 



OpliiiMjlussiuri iindicatile fitwrni; Mart. Fl. Bras, l'' : 144. 1840, not L. f. 

 South Carolina to Florida, west to Louisiana. Also in Arizona. 



Ophioglossum crotalophoroides Walt. Fl. Car. 256. 1788. 

 Ophiogkmujn hulhoxdin :Michx. Fl. Bor. Am. 2 : 276. 1803. 

 South Carolina and Florida; Alabama, westward to Texas. 



CHEIROGLOSSA Presl, Abh. Kon. Bohm. Gesell. Wiss. V. 



4 : 316. 1847. 



Cheiroglossapalmata(L.) Presl. Abh. Kon. Bohm. Gesell. Wiss. V. 4:317. 

 1847. 



Of)h!nglo><sum pahnatiuii L. Sp. PI. 10(33. 1753. 

 Florida. 



