kEfRODUCTlVE APPENDAGES. CHAP; IV. 



the base of both. If it is situated at the base of 

 the general i-mbel, it is a general involucre ; and 

 if at the base of the partial umbel, it is a partial in- 

 volucre. In some species it wholly surrounds the 

 stem or peduncle in a ring or whirl, as in Daucus ; 

 in others it surrounds it only by the one half, as in 

 JEthusa* In the former case it is said to be com- 

 plete ; and in the latter it is said to be dimidiate. 

 Its figure. Its figure is generally strap-shaped, if consisting 

 of one leaf; and if consisting of more than one leaf, 

 the individual leaves are so. But sometimes the in- 

 dividual leaves are also egg-shaped acute, as in 

 Bupleurum ; and sometimes they are bristle-shaped, 

 as in Cicuta. The structure of the leaves com- 

 posing it is either undivided, as in Caucalis ; or 

 divided into several segments, as in Daucus, in 

 which also they are edged with a membranaceoua 

 border towards the base, and wing-cleft towards the 

 apex. 



If it consists of one leaf it is said to be mono- 

 phyllous ; if of two leaves it is said to be diphyl- 

 lous ; and if of many leaves polyphyllous. 

 Regarded Linnaeus who adopted and introduced the term 

 omasa involucre, or at least the less harsh and wholly 

 **!* Latin term iwcolucrum, at the suggestion, as it ap- 

 pears, of his friend Artedi, regarded the part desig- 

 nated by it as a calyx remote from the flower, and 

 peculiar to the umbel.* Analogy does not however 

 justify this view of the subject, because the flowers 

 * Phil, Bot. sect. 8tf. 



