70 BOTANICAL GAZETTE [JANUARY 
at Bismarck, Missouri, in November of the previous year. He notes 
that “‘the air was rather moist. ‘Temperature below freezing point in 
the shade. Soil moist. Plants recently dead. Plates (crystals of ice) — 
noted about 2 to 5 p.M. on plants in shade —as though formed over 
night and melted elsewhere. At the same time similar crystals were 
seen on the soil and pebbles along paths.” + 
Mr. F. E. Hand has observed the frost ribbons on Cunila Mariana 
in Kentucky. 
| Mr. Valerio described the occurrence of such formations in Alabama 
as follows.® 
On January 27 the minimum temperature at this station was 14°. The 
next morning, going down the hillside by my house I noticed, on the dry 
grass and low brush, what at first sight I took for snow and nearer for bunches 
of cotton, but which on closer examination I found to be frostwork of a very 
peculiar shape and form, looking very much like fine stick or ribbon candy, or 
fine Venetian glass. These ribbons, beautifully curled and feather-like, came 
out from the stubs of the plants and, from a sample which | inclose, you will. 
notice the bark was taken off the plants. The width of the frost ribbon — 
was as the length of the cracks in the plant. They looked like fine shavings 
of a very white wood and crumbled at the touch. 
Dr. Cleveland Abbe says concerning the formation of ice columns 
on soils: “It is undoubtedly not only very common in our latitudes 
and soils, but is also quite an important item in agricultural - 
physics.” The formation of such crystals on the surface of the soil - 3 
due primarily to the freezing of the upper portion of the hygroscople — 
water on the soil particles and its elevation by the successive films of 
liquid water which replace it. A very ingenious and delicate exper: — 
ment is suggested in imitation of this action. In regard to frost crys 
tals on plants Dr. Abbe says: “When the outer air is frosty, while 
the sap is pressing up the body of the tree, a thin film of moisture may 
possibly be supplied from within as fast as the outer film at the surface 
of the crack may be frozen and lifted, and may thus form the exudation 
from the trees.” 
The notes given above establish quite clearly that the frost crystals 
which appear to exude from the tissues of dead plants are due x 
physical conditions quite similar to those found in soils, and to be ™ 
5 Monthly Weath. Rev. July 1897. 
° Rep. Climate and Crop Service, Jan. 1895. 
7 Am. Meteor. Jour. 9: 523. 1893. 
