486 General Notes. [August, 
OBSERVATIONS ON SILPHIUM LACINIATUM, THE s0-CALLED COM- 
Pass Praxt.!— For the past six or eight years there has been little 
doubt of the curious polarity of the root and stem-leaves of the large 
coarse plant known throughout the prairie regions by the name of the 
compass plant. It appears, however, that few accurate measurements of 
the bearings of these leaves have been made. So that while they are 
now considered as pointing more or Iess to the north, but little is known 
as to how nearly they arrange themselves upon the meridian. In order 
to contribute to a better knowledge of this matter, I have for several 
years been making observations, the results of which I herewith trans- 
mit : — 
TABLE I. 
Bearings of the leaves of fourteen small plants, many of which had but one leaf 
hs — 
North 1° 30 East. North 4° 30 West. 
ce 1° 45/ ee “ 70 80/ ce 
“ 1° 45! “ “ 8 30! “ 
sna po ao s © O°. Iy f 
“ce 6° Qo! “ ic 130 30' cc 
ae 6° 80’ “ ee 990 15/ é 
“ go o “ “ 25° or “ 
“ec 91° 30 “ee “ 29° 30/ e 
“ 820 $0! ét “ec 34° 0’ “ 
$e BAC. Oy ot" 
" Eo w r 
" epe ? 
o pcan arden ts 
Fifty per cent., it will be observed, deviated less than ten degrees, and 
eighty-six per cent. less than forty-five degrees from the meridian. 
TABLE II. 
Bearings of thirteen leaves, all of which grew on one large plant : — 
North 0° 30! East. North 0° ‘30! West. 
4 0° 45! “ce “ 1° 1 5 “ 
“ce 8° 80! ce “ce 350 80/ “ee 
Las 3° 45/ “ “ee 889 of fig 
“ 3° 5/ “ 
oe eer 
a e 30 
“c 86° 0! ég 
“ 899 30! itd 
Fifty-four per cent. of these leaves deviated less than four degrees 
from the meridian, and eighty-five per cent. less than forty-five degrees- 
TABLE III. 
Bearings of the leaves of a medium sized plant : — 
North 1° Of East. : North 0° 15! West. 
dante 1° 30’ ce ce 0° 30/ cg 
« 0° 30’ w 
“ 20° o e 
paar 4 569 o/ “ 
1 See an article on this ei in Tue Amertcan Naturatist for March, 1871, 
posa may be found also references to other papers. An article appeared some years 
a in the American Agriculturist, and another recently in Nature, in which £ 
cnt fh compass plant wore ie, 
