14 THE FLORIST AND 
ICE-RIBBANDS OK PLANTS. 
I was interested in perusing an article in the last number of the Florist, 
on the "effect of frost on certain plants." Having had occasion to observe 
the said effect in a plant which is not mentioned, as being subject to it, by 
any writer within my knowledge, and yet one in which that curious phe- 
nomenon occurs in the most beautiful forms : I mean the Ounila Mariana, 
L. or Dittany. While engaged in exploring the route for the West Chester 
railway, through the woodlands on the slaty hills north of that borough, 
one frosty morning after a rain, in the beginning of winter, 1830, my atten- 
tion was arrested by an abundance of beautiful crystalline ribbands, attached 
to the dead stems of the Dittany, near their base, in the form of what are 
commonly called "bow knots." Those bowed Ice-ribbands issued in oppo- 
site pairs from slits in the square stems of the plants, and were one-third 
to half an inch wide, striated, and brilliantly pretty in the morning sun. 
BiGELOW and Eaton had observed something similar in the HeliantJie- 
mum Canadense, Mx., and Elliott has the following, in reference to 
Qonyza [Pluchea) bifrons, L. "This plant exhibits frequently a remark- 
able phenomenon. In every clear frosty morning during the winter, crys- 
talline fibres nearly an inch in length shoot out in every direction from the 
base of the stem. It would appear as if the remnant of the sap, or water 
absorbed by the decayed stem had congealed, and had burst in this manner 
through the pores of the bark. Does this proceed from any essential quality 
of the plant, or from its structure?" De Candolle {under Fluchea), cites 
the substance of Elliott's remarks, in these words: "Per hiemem in horis 
matutinis, si coelum serenum. Librae cristallinse poUicem longae ^ basi caulis 
oriuntur !" The phenomenon, though so frequent here, seems to be regarded 
as something strange in Europe. No one, even in this country, appears to 
have observed the effect of frost upon the Ounila ; although I think the pro- 
duct more conspicuous and symmetrical, (perhaps in consequence of the 
quadrangular stems,*) and the ribband-like crystals, more than twice the 
length of those mentioned by the authors referred to. In the Flora Cestrica, 
published in 1837, the following remarks were subjoined to the description 
of Ounila Mariana: — "In the beginning of winter, after a rain, very curi- 
ous and fantastic ribbands of ice may often be observed, attached to the 
* May not tlie manner in wliich the crystals issue, be regulated by the structure and shape 
of the stem ? The Cunila, with its four-sided stems, has the crystals issuing through slits, in 
the opposite, flat sides; while from the terete stems of the Pluchea, they "shoot out in every 
direction." 
