L YCOPODIA CE.-E. 1 3 5 



in a single series. Southern California in open canons {AIc- 

 Clatchte). 



ft Branches rare except taken the main stem is broken, 

 \ Stems rough, ticberculate. 



10. E. robustum A. Br. Stems 3' — 11" high, sometimes 

 nearly i' thick, 20 — 48 furrowed; ridges roughened with a 

 single series of tubercles; sheaths short, marked with black 

 girdles at base and at base of the caducous teeth ; ridges of 

 sheaths tricarinate. Ohio to California and northward. 



11. E. hiemale L. (SCOURING-RUSH.) Stems 1° — 4° high, 

 8—34 furrowed; ridges rough, with two indistinct lines of tu- 

 bercles; sheaths rather long, marked with one or two black 

 girdles; ridges of the sheath obscurely quadricarinate. North 

 America generally. 



\\ Stems smoothish, scarcely tiiberculate. 



12. E. laevigatum A. Br. Stems v — 5° high, pale green, 

 14 — 30 furrowed ; ridges almost smooth ; sheaths elongate, en- 

 larged upward, marked with a black girdle at the base of the 

 mostly deciduous white-margined teeth, rarely with a second ; 

 ridges of sheath with central keel and rarely faint lateral ones. 

 North Carolina to California and Oregon. 



** Stems slender, tufted, 5 — \o grooiied. 



13. E. variegatum Schleich. Stems ascending, 6' — 18' 

 long, usually simple from a branched base, 5 — 10 furrowed ; 

 sheaths green, variegated with black above, the teeth 5 — 10, 

 tipped with a deciduous bristle ; central air-cavity small. Bel- 

 lows Falls. New Hampshire {Carey), Niagara Falls to Illinois 

 and northward to Greenland and Alaska. 



14. E. scirpoides Michx. Stems filiform, very numerous, 

 3' — 6' high, flexuous and curving, mostly 6-furrowed, with acute 

 ridges ; sheaths 3-toothed, the bristle tips more persistent ; cen- 

 tral air-cavity wanting. New England to Pennsylvania, Illinois 

 and northward. 



ORDER VI. LYCOPODIACEiE Lindl. 



Moss-like, terrestrial plants with small, lanceolate or subu- 

 late, sometimes oblong or roundish, simple leaves, arranged in 



