360 



THE FLORIST AND 



formed in this way on the plant, by causes similar to those which exist in 

 the soil. Our limits prevent our examining other parts of Le Conte's 

 explanation, or pointing out the errors which seem to be involved in it. 

 But allowing that this is sufficient to account for the formation of the com- 

 pact fibrous masses of Lantana, it does not apply to the lamellar sheets 

 which surround the stems of other plants. Dr. Caspary therefore inquires 

 what organs there are in • plants disposed with sufficient regularity and of 

 proper length to give rise to plates extending sometimes several inches down 

 the stem, and thrusting off the bark in every direction. 



The only organs answerable to this character are the vascular bundles, 

 and to these therefore his attention has been turned. In all the instances 

 which came under his observation, he found the walls of the vessels pitted, 

 and the only difficulty of great consequence which met him, was the 

 uncertainty that exists as to the functions of the vessels. That they con- 

 tain fluid at an early stage is certain, because they are but modifications of 

 cells ; but whether they carry fluid when arrived at maturity, except with 

 rare exceptions, is far from certain. Allowing that they were gorged with 

 fluid, in the plants in question, the lateral pores might readily convey it to 

 the neighboring elongated tissue, and so be subjected to the freezing tem- 

 perature which had penetrated through the bark. It seems, however, to us 

 quite as probable that the fluid might be more energetically carried through 

 the cells with which the vascular bundles are surrounded, than through the 

 neighboring tissue ; and if so, we have a series of lines corresponding with 



the vessels, where the icy plates 

 might be formed, without assuming 

 the doubtful position that water is 

 carried through vessels which seem 

 more peculiarly destined to convey 

 air, with rapidity and abundance 

 sufficient to produce the enormous 

 masses of ice which appear upon 

 the stems — masses which have a 

 very high ratio to the quantity of 

 water which could pass through the 

 plant within the time of the forma- 

 tion of the ice, under any ordinary circumstatances. 



