PERSPIRATION OF PLANTS. 25 



with this dust ; and several succulent plants have 

 a great abundance of it, though the number of 

 their pores is inconsiderable. 



M. Deeandolle believes them to be organs of 

 insensible perspiration, which is common to all 

 vegetables ; aquatic and submersed plants perhaps 

 excepted, in which pores in facT: are not found. 

 The succulent plants, which have very few, per- 

 spire but little. — He conceives it also probable 

 that the pores in certain cases serve to absorb 

 moisture. 



EXPLANATION OF PLATE I. 



Fig. ** Scale of the relative magnitude, each part being en- 

 larged 62 times in its linear dimensions. 



Fig. 1. The ~ part of a line of the cuticle on the lower 

 surface of a seed-lobe of Perilla ocymoides. 



Fig. 2. The same of the seed-lobes of the stock gillyflower 

 (Cheiranthus incanus.) 



Fig. 3. The same of a leaf of the red lily (Lilium bulbiferum.) 



Fig. 4. Of the corolla or calyx of the same plant. 



Fig. 5. The same of the common onion (Allium Cepa.) 



Fig. 6. Of a leaf of Indian Corn (Zea Mays.) 



