140 ORGANOGUAPHY. BOOK I. 



law ill real leaves, il is natural that it should not be departed 

 from in any modifications of them. 



When the petals of a corolla are all distinct, then the 

 corolla is said to be imlypetalom ; but if they cohere at all by 

 their contiguous margins, so as to form a tube, it then be- 

 comes what is called monojjetalous ; an inaccurate term of the 

 same origin as that of monophyllous, in regard to calyx {see 

 p. 138.), and for whicli that o^ ganiopetalous has been some- 

 times substituted. 



If the petals adhere to the bases of the stamens, so as to 

 form a sort of spurious monopetalous corolla, as in Malva 

 and Camellia, such a corolla has been occasionally called 

 catapetalous ; but this term is never used, all such corollas 

 being considered polypetalous. 



When the petals are confluent into a monopetalous corolla, 

 they constitute what is called a tube; the orifice of which is 

 the faux or th'oat. The principal forms of such a corolla 

 are rotate {Jig. 94.), hypocrateriform {Jig. 92.), infundibu- 

 liform {Jig. 95.), campanulate {Jig. 69.), and labiate {Jig. 93.). 

 When the divisions of a monopetalous corolla do not, as in 

 Campanula, spread regularly round their centre, but part 

 take a direction upwards, and the remainder a direction 

 downwards, as in Labiatte, the upper form what is called the 

 upper lip, and the lower, the lorcer lip, or lahellum ; the latter 

 term is chiefly applied to the lower lip of Orchideous plants. 

 If the upper lip is arched, as in Lamium album, it is termed 

 the galea or helmet. When the two lips are separated from 

 each other by a wide regular orifice, as in Lamium, the 

 corolla is said to be labiate or ringent ; if the upper and lower 

 sides of the orifice are pressed together, as in Antirrhinum, it 

 is personate or masked, resembling the face of some grinning 

 animal. In the latter the lower side of the orifice is elevated 

 into two longitudinal ridges, divided by a depression corre- 

 sponding to the sinus of the lip ; this part of the orifice is 

 called the palate. In ringent and personate corollas the 

 orifice is sometimes named the rictus ; but this tei'm is super- 

 fluous and little used. 



A petal consists of the following parts : — the limb or lamina 

 (lame, Fr.) ; and the iuiguii< or ciaio (onglet, Fr.). The claw 



