92 VEGETABLE ORGANOGRAPHY. 



CHAPTER X. 



OF HAIRS. 



Section I. — Of Hairs in general. 



Under the common name of Hairs (j)ili, villi; poils) 

 are generally described all those little soft filiform pro- 

 ductions which are observed upon the surface of plants, 

 and which, in fact, greatly resemble the hairs of animals 

 in their form, and, in some respects, in their structure 

 and history. 



The Hairs of plants are entirely prolongations of one 

 or several cellules, which, by their projection, are pro- 

 minent above the surface ; thus, between a Vesicular 

 Gland, for example, and a Hair, there is no other differ- 

 ence than the peculiar form of the two organs. We 

 ought to distinguish several classes of hairs, which only 

 resemble each other in their general form, but differ 

 much in their use, their origin, and their structure : in 

 each of these classes we may range several kinds of hairs, 

 which have received particular names in botanical works. 

 Guettard, who first attentively observed them, and who, 

 from this examination, endeavoured to classify plants, 

 has multiplied the terms relating to these organs ; and 



