140 
ORGANOGRAPHY. 
BOOK I. 
law in real leaves, it 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 polypetalous ; but if they cohere at all by 
their contiguous margins, so as to form a tube, it then be- 
comes what is called monopetalous ; an inaccurate term of the 
same origin as that of monophyllous, in regard to calyx {see 
p. 138.), and for which that of gamopetalous 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 throat 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 Labiatae, the upper form what is called the 
upper lip, and the lower, the lower 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 jmlate. In ringent and personate corollas the 
orifice is sometimes named the rictus ; but this term is super- 
fluous and little used. 
" A petal consists of the following parts : — the limb or lamina 
(lame, Fr,) ; and the unguis or claw (onglet, Fr,), The claw 
