OF THE INVOLUCRUM. 187 



in the Pinks, .61, 62, or the globular scaly cup in 

 Centaurea, t. 56. The Tulip, t. 63, is a naked 

 flower, having no calyx at all. 



This part is of an infinite variety of forms in 

 different genera, being either simple or compound, 

 divided or undivided, regular or irregular. In some 

 instances it is permanent till the fruit is ripe, in others 

 it falls even before the flower is well expanded. 



Some genera have a double perianthium, as 

 Malva, t. 671, or even a triple one, as Scabiosa, 

 t. 1311. 



2. Involucrum,f. 143. Involucre of Professor Marty n; 

 but I generally retain the Latin termination. This 

 is remote from the flower, and can scarcely be di- 

 stinguished clearly from a Bractea. The term was 

 first adopted by Linnaeus, at the suggestion of his 

 friend Artedi, in order to distinguish the genera of 

 umbelliferous plants, for which purpose the latter 

 deemed the part in question very important. But 

 according to the laws which Linnaeus had laid 

 down, the parts of the flower and fruit alone were to 

 afford generic characters, and the most sound bota- 

 nists have ever since kept to this rule, with infinite 

 advantage over less correct ones, however ready to 

 derive ideas respecting the natural habit, and secon- 

 dary characters, of a genus, not only from the in- 

 florescence and bracteas, but even from the leaves, 

 stipulas, or other parts. Linnaeus and Artedi, there- 



