Nov., 1912.] An Undescribed Equisetum from Kansas. 
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In size and manner of growth this new species is closely allied 
to E. hyemale, and the larger variety of E. robustum, but it is 
easily distinguished by its smoothness, its long green sheaths, 
with a narrow black limb, and its darker green color.” 
This description seems to be quite accurate except is some 
minor points. The color is usually not darker green than in E. 
hyemale and the sheaths are usually though not always dilated 
above. The color of the large Equisetums varies considerably 
with the environment, and in some cases the young sheaths are 
more or less dilated than the old ones. 
The new species may be characterized as follows: 
Equisetum kansanum n. sp. 
Kansas Horsetail. 
Aerial stems usually 1-2]^ feet high, annual, very smooth, 
15-30 grooved, usually without simple branches unless broken 
off; color mostly light-green; surface of the ridges and grooves 
with cross or diagonal bands; sheaths long, dilated above and 
visually constricted at the base, green with a narrow black band 
at the top; teeth deciduous; cones ovate or oblong-ovate, without 
a point, the apex obtuse or merely acute. On upland clayey 
banks along ravines and hillsides, growing in rather scattered 
tufts. Name derived from Kansas where the species is common. 
Type locality, Bloom township, Clay County, Kansas. Speci¬ 
mens also from Mancos, Colorado. Type and cotype 1 deposited 
in the herbarium of the Ohio State University, Columbus, Ohio. 
Equisetum laevigatum and Equisetum kansanum form the 
transition types between the large, evergreen scouring-rushes 
like E. hyemale and E. robustum on the one hand and the tall 
annual horsetails, like E. fluviatile on the other. E. laevigatum 
is perennial in Kansas although it often freezes down to near the 
surface of the ground in severe winters. 
The habit of growth between the three species which are often 
confused is quite characteristic. E. hyemale grows in dense 
masses usually on creek and river banks and low places. E. 
laevigatum is rather tall and is more open and separate in its 
growth, abounding in Kansas, in sandy river bottoms where the 
soil is well filled with clay or other fine material and at the base 
of clayey bluffs. E. kansanum as stated above is also open and 
scattered in growth and is found mainly on clay banks along 
ravines and hillsides. They may be readily separated by the 
following key: 
