Vhilomatic Society — Botany, 177 



which had leaves raifed the mercury 4-64 inches in nine 

 hours, while the mifTeltoe deprived of its leaves raifed it 

 only 1*5 : the leaves of the mifleltoe, therefore, a<St the fame 

 part in regard to the apple-tree as the real leaves of that tree. 



4th. Having taken two milTeltocs with leaves, one of which 

 was implanted on a part of the root of the apple-tree, and 

 the other immerfed immediately in water ; and having dif- 

 pofed them as in the preceding experiment, the firft mifleltoe 

 raifed the mercury about 4*48 inches; the other once 

 raifed it '42, and another time did not raife it at all/ This 

 lingular experiment Ihows, that the mifleltoe, by itfelf, is aU 

 moll: entirely deilitute of the faculty of railing the fap. 



Decandolle on this occafion obferves, that the faculty of 

 railing the fap by a root is intimately conneded with a per- 

 pendicular dire6lion. In regard to their nutrition, he divides 

 vegetables into two clafles. The firft receive their nourifh- 

 ment throucrh their whole furface ; do not live but in one fur- 

 rounding medium, of air, as the lichens; of water, as the fuci ; 

 or of earth, as mufhrooms. Vegetables of the firft clafs have 

 no tendency to a perpendicular dire6lion. Thofe of the fe- 

 cond receive their nouri(hment through a determinate place 

 called their root: they always live in two or three furround- 

 ing mediums ; in the earth and water, like the potamogetons ; 

 -in water and air, as the Jlratiotes ; in the earth and air, as the 

 oak ; in the earth, water, and air, as the nymphaea. The 

 plants of the fecond clafs all tend to the zenith with more or 

 lefs energy. 



Decandolle has alfo read a memoir on the pores and the 

 bark of leaves. The word gland in the anatomy of animals 

 fignifies a fecretory organ ; but in the anatomy of plants this 

 name has been given to feveral organs which are not, or at 

 leaft have never yet been known to be, fecretory organs, and 

 which differ confiderably from each other. The miliary 

 glands of Guettard have particularly fixed the attention of 

 Decandolle ; they are thofe which De Sauifure has defcribed 

 under the name of cortical glands, and which by Hedwig 

 are called vafa ly?nphatica cuticul^. Decandolle gives them 

 the name oi cortical fores ) an appellation that relates only to 

 ■ their form and their pofition, which are certain things^ and 



Z "not 



