‘ 
NortH AMERICAN EQuIsETUM 71 
a. Sterile stem ivory white or brownish, 2-10 ft. high, its 
branches several-angled, terete; fertile stem usually 1-2 ft. 
high, robust, the internodes usually without stomata, the 
sheaths including the 20-30 long teeth 114-2 in. long; cone 
2-3 in. long, its axis hollow. . telmateia. 
. Sterile stem green or brownish in age, usually less than 2 
ft. high, its branches sharply 3-or 4-angled; fertile stem 
14-1 ft. high, the internodes with stomata, the sheaths in- 
cluding the 7-15 teeth 34-114 in. long; cone 1-14 in. long, 
its axis solid when young. Z£. arvense 
= 
LIST OF NORTH AMERICAN SPECIES. 
1, EquiseTruM LAEVIGATUM A. Br. Am. Jour. Sci. 46: 87. 
1844. Smooth Scouring-rush. 
E. hiemale intermedium A. A. Eat. 
Type locality: ‘On poor clayey soil, at the foot of the 
rocky ee ee on the banks of the river below 
St. Louis,’’? Miss 
In various aae commonly on flood plains, along 
streams and rivers; rather open in its growth. 
Conn., N. Y., and Ont. to B. C., south to Cal., N. 
Mex., Tex., La., and N. C. 
2. EQuIsETUM PRAEALTUM Raf. Florula Ludoviciana 13. 
1817. Great Scouring-rush. 
E. robustum A. Br. E. affine Engelm. LE. ferrissi 
Clute. 
Type locality: “Banks of the Mississippi River,” 
Louisiana. 
Mostly on moist, usually alluvial soil especially along 
brooks, creeks, and rivers commonly forming dense 
masses or shake stands. 
Conn. and Quebec to B. C. aoathward nearly through- 
out the United States to Cal., Northern Mex., La., and 
N.S 
3. EQUuISETUM HIEMALE L. Sp. Pl. 1062. 1753. Rough 
Scouring-rush. 
Incl. E. hiemale californicum Milde. 
Type locality: ‘Habitat in Pineee sylvis, aspris, 
uliginosis.’”’ 
