LECT. XJ.] CAULINAR AND FOLIAR APPENDAGES. 637 



gland-bearing stalk at its base. These glands ge- 

 nerally secrete a viscous resinous matter, which 

 is also sometimes odorous. 



The minuteness of the vegetable glands pre- 

 vents me from attempting to offer you any anato- 

 mical demonstration of their structure. They 

 have, indeed, been arranged into cellular and vas- 

 cular glands by writers who have endeavoured to 

 trace their structure, and who have stated some of 

 them to be entirely cellular, and others chiefly 

 vascular ; but as we can scarcely suppose that any 

 part, completely devoid of vessels, possesses the 

 function of secretion, we must receive these state- 

 ments with caution. With regard to the use of 

 glands to the plant, at least as far as relates to 

 the conservative organs, we know nothing. They, 

 probably, do not play so important a part in the 

 vegetable as in the animal economy ; but we can 

 hazard nothing more than conjecture on the sub- 

 ject. 



ii. PUBESCENCE, Pubescentia. Under this term 

 are included all the kinds of down, hairs, and 

 bristle-like bodies, found on the surfaces of the 

 conservative organs. They differ very considerably 

 in form and texture, and on these differences I 

 shall attempt such an arrangement of them as 

 may facilitate your knowledge of the subject. 



All vegetable pubescence consists of small, 

 slender bodies, which are either soft and yielding 

 to the slightest impression, or *rigid and compa- 



