ON FaESH-WATER PLANTS. 24^ 



seen the bubbles of air formed by a brisk blowing wind 

 cover a plant, till it appeared as if rolled in diamonds : but 

 when 1 have drawn off the upper cuticle of the leaf, and 

 subjected it to the solar microscope, not a single aperture 

 could be discovered, and the marks proved as usual to be 

 only the indentations of the pabulum seen through the 

 cuticle. 



To this I shall add the parts that belong to each different 

 sort of plant, which will elucidate the subject, and show 

 the confusion which must arise from not properly discri- 

 minating them, 



I am. Sir, 



Your obliged servant, 



AGNES IBBETSON. 



Different Parts of each various Sort of Matter found in the 

 different Stems of PlantSy and arranged in the manner they 

 pass from the exterior to the interior Parts. 



In trees in general. — Rind, bark, inner bark vessels, wood. Structure of 

 spiral vessels wound round the inner wood vessels, line of p^J^^^^j^"* ^^ 

 life, pith ; bud proceeding from the nearest line of life, 

 whether in stem or twig. 



Fir trees, -r-hesixes cover instead of rind and bark, and 

 thicken by degrees, having the inner bark vessels within the 

 leaves : a thick row of wood, resembling the common wood, 

 placed as a screen to guard the new wood from the delete- 

 rious effect of the juices : hard wood, line of life, pith: bud 

 as usual in trees. 



Shrubs -Rind, bark, inner bark vessels, wood, spiral 



vessels, line of life, pith : bud as usual in trees. 



Herbaceous P/an/s.—Rind, bark, inner bark vessels, wood, 

 line of life within the pith, wood generally in rows, in num- 

 ber according to the length of the season : buds shooting 

 from the interior of the pith, of course forming the line of 

 life. 



Annual and semiplants.^R'ind, bark, inner bark vessels, 

 wood in circular vessels, half wood half clear albumen, scat,- 

 terjedinthe pith, with the spiral vessels within the wood, 

 and having the line of life within the pith. 



Fresh* 



