Fantastic Frost Crystals on Dried Stems of Dittany 
Raymond N. TORREY 
Frost crystals on certain plants, appearing late in autumn, 
or in early spring are occasionally reported in botanical litera- 
ture. The crystals which shoot from the bases of the stems of 
Helianthemum canadense and majus have given both of these 
species the popular name of Frostweed. Probably the same phe- 
nomenon appears on other plants, although I have not seen it 
reported in the manuals. Thoreau, in “Early Spring in Massa- 
chusetts,” page 279, refers to ‘frost bodkins,” needle like cry- 
stals on the roots of Herd’s Grass, or Timothy, Phleum pratense, 
observed on March 29, 1859, in Concord. 
I noticed an extraordinary example of such frost crystals on 
Dittany, Cunila origanoides, on November 27, on an old wood 
road on the east side of Kittatiny Mountain, near Mount 
Vernon, in Warren County, New Jersey. More than twenty of 
these odd forms were noted, and all were on the dead, dried 
stems of Dittany. Nothing of the kind was to be seen on other 
dead stems of herbaceous plants along the road, such as asters, 
goldenrod, grasses, etc. There appeared to be some reason, pos- 
sibly in the square structure of the stem, some facility for capil- 
lary movement upward from the soil of moisture, which froze 
into these fantastic crystals, but what it may be would require 
some study and close observation from the moment of the be- 
ginning of the building out of these fragile and beautiful shells 
of ice. 
The crystals appeared to have grown out from the base of 
the dried stems, an inch or two above the ground. In height, 
vertically, along the stem, they were 2 or 3 inches. Their width 
was Irom 2 to 4 inches; their thickness about 1-32 of an inch. 
In structure, they suggested the concentric curves of the bracket 
fungus, built out horizontally by curving lines of cell growth from 
a base on a dead or diseased tree. 
These ice crystals seemed to have grown in similar concen- 
tric curves, but vertically, beginning with a band 4 inch to 1 
long, where moisture issuing from the stem froze, and then an- 
other froze over it and soon. Some of these flat, vertically placed 
crystals showed a dozen or more such bands, from 1-32 to 1-16 
and 1-8 inch wide increasing in width from the stem outward. 
The outer edge tended to be wavy, fluted or crisped. Sometimes 
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