POLYPODIACEAE. 5 



14. BELVISIA Mirb. 



i. Belvisia septentrionalis (L.) Mirb. (Asplenium septentrionale Hoffm.) 

 On rocks, S. D. to Mont., N. M. and Ariz. Alt. 6000-6500 ft. Horsetooth 

 Mountain; South Boulder Canon; Arkansas Canon. 



Orders. SALVINIALES. 

 Family 3. MARSILEACEAE R. Br. MARSILIA FAMILY. 



i. MARSILEA L. 



i. Marsilea vestita Hook. & Grev. Wet, sandy soil, Ark. and Tex. to 

 Calif., B. C. and S. D. Saguache (Wolf). 



Order 4. EQUISETALES. 



Family 4. EQUISETACEAE Michx. HORSETAIL FAMILY. 

 i. EQUISETUM L. HORSETAIL. 



Stems annual, copiously branching. 



Spike-bearing stems pale, soon withering; sheaths of branches 4-toothed. 



i. E. arvense. 

 Spike-bearing stems withering at apex, producing branches below ; sheaths of 



branches 3-toothed. 2. E. pratense. 



Stems perennial, evergreen ; branches few. 



Stems smoothish, i4~3o-furrowed. 3. E. laevigatum. 



Stems roughened, 5-io-furrowed. 4. E. variegatum. 



1. Equisetum arvense L. In sandy places, Greenl. and Va. to Calif, and 

 Alaska. Alt. 5000-10,000 ft. Fort Collins; Ouray; West Indian Creek; 

 Mancos; Bob Creek, west of Mt. Hesperus; Hotchkiss. 



2. Equisetum pratense Ehrh. Along streams, N. Sc. to N. J., Colo, and 

 Neb. Alt. up to 10,500 ft. Bob Creek, west of Mt. Hesperus. 



3. Equisetum laevigatum A. Br. Moist places, N. J. to Tex., B. C and 

 Calif. Alt. 4000-12,500 ft. Gunnison; Parlin; Ft. Collins; West Spanish 

 Peak; Cucharas River, below La Veta; Wahatoya Creek; Trimble Springs; 

 Mancos; Grand Junction. 



4. Equisetum variegatum Schleich. In sandy soil, Arctic America to N. 

 Y. and Nev. Clear Creek, near Denver (Coulter}. 



Orders. ISOETALES. 



Family 5. ISOETACEAE Horan. QUILLWORT FAMILY. 

 i. ISOETES L. QUILLWORT. 



Stomata wanting ; leaves 40-60, rigid ; microspores whitish, papillose. 



1. /. paupercula. 

 Stomata present ; leaves 5-25, soft ; microspores deep brown, spinulose. 



2. L Bolanderi. 



i. Isoetes paupercula (Engelm.) A. A. Eaton. [7. occidental Henderson, 

 /. lacustris paupercula Engelm.] In lakes, always submerged; Colo, to Calif., 

 Wash, and Ida. Grand Lake, Middle Park. 



