General Key to the Families 



IX. ASPIDIUM. Sw. 



1. A. Filix-mas. (L.) Sw. Male Shield Fern. 



2. A. spinulosum var. dilatatum. (Hoffm.) Hook. 



Spinulose Shield Fern. 



3. A. Oreopteris. Sw. Scaly Shield Fern. 

 X. CYSTOPTERIS. Bernh. 



1. C. fragilis. (L.) Bernh. Brittle Fern. 



2. C. montana. (Lam.) Bernh. Mountain Bladder 



Fern. 



II. OPHIOGLOSSACE^. ADDER'S TONGUE FAMILY 



Leafy, fleshy plants; leaves simple or branched, fern-like, erect 

 in vernation, the bud placed either inside the base of the old stalk 

 or beside it ; sporangia borne in spikes or panicles formed from the 

 main tissue of the fruiting branches. 



I. BOTRYCHIUM. Sw. 



1. B. Lunaria. (L.) Sw. Moonwort. 



2. B. simplex. E. Small Moonwort. 



3. B. virginianum. (L.) Sw. Rattlesnake Fern. 



4. B. lanceolatum. (Gmel.) Angstroem. Slender 



Moonwort. 



ORDER II. EQUISETALES 

 III. EQUISETACE^. HORSETAIL FAMILY 



Rush-like green plants with jointed usually hollow stems from 

 running rootstocks; the branches verticillate, with toothed sheaths 

 at the nodes, and when fertile bearing the sporangia beneath the 

 scales of the terminal cone-shaped spikes. 



I. EQUISETUM. (Tourn.) L. 



1. E. arvense. L. Field Horsetail. 



2. E. pratense. Ehrh. Thicket Horsetail. 



3. E. sylvaticum. L. Wood Horsetail. 



4. E. scirpoides. Michx. Rush Pipes. 



5. E. fluviatile. L. Swamp Horsetail. 



6. E. variegatum. Schleich. Variegated Horsetail. 



7. E. hyemale. L. Scouring Rush. 



