Nov., 1912.] An Undescribed Equisetum from Kansas. 
19 
AN UNDESCRIBED EQUISETUM FROM KANSAS.* 
John H. Schaffner. 
For many years the writer has known a peculiar type of 
Equisetum with annual, aerial stems, growing on clayey banks 
and bluffs in central Kansas. This plant was referred to Braun’s 
Equisetum laevigatum, although some of its most evident charac¬ 
ters did not agree with the description of that species. 
In 1903 (Fern Bull. 11 : 40), Eaton stated that according to 
his observations, E. laevigatum A. Br. was annual and this view 
is continued in Gray’s Manual, 7th Ed. 1908, where the state¬ 
ment is made that the stems are “mostly annual. ” In a note in 
the Ohio Naturalist, 4 : 74, the writer agreed with Eaton and also 
suggested that E. laevigatum as at present understood might be a 
composite species. Eaton described E. hyemale intermedium 
and stated that it was “often confused with E. laevigatum. ” 
The writer has had the various forms of Equisetum, which are 
involved in the confusion, under consideration since 1903 and has 
come to some definite conclusions which are here presented: 
1. The annual form of Equisetum from the west usually 
going under the name E. laevigatum A. Br. is an undescribed 
species. 
2. Braun’s description of E. laevigatum is essentially correct. 
3. Eaton’s E. hyemale var. intermedium is Braun’s E. 
laevigatum. 
The writer examined the original material at St. Louis from 
which Engelmann sent specimens to Braun, and found that the 
plants agree well with Braun’s description. They are perennial 
and the cones have a definite point. They are considerably 
smoother than the usual forms of E. hyemale but much rougher 
than the disputed plants from Kansas. 
One of Engelmann’s specimens of E. laevigatum A. Br. dis¬ 
tinguished as variety B, scabrellum, collected in August, 1843, on 
the banks of the Mississippi below Jefferson Banks is marked in 
pencil as “Probably type specimen.” Both branched and un¬ 
branched specimens are in the collection. This specimen has no 
cones. Another specimen labeled E. laevigatum A. Br. from 
sterile hills near harbors nine miles west of St. Louis, July, 1844, 
has the cone with a rigid point and agrees with the specimens the 
writer identified as E. laevigatum, the past summer in a trip to 
Kansas. It has the long dilated sheath and other distinguishing 
characters. 
*Contribution from the botanical laboratory of Ohio State University, 
No. 70. 
