ANGIOSPERMS. 
539 
it continues to develope, the part common to the whole whorl of floral leaves. 
The coherent tubular or campanulate part does not therefore consist of originally 
free portions which cohere subsequently by their edges, but from the very first it 
forms a whole which is intruded, so to speak, at the base of the perianth-leaves ; 
the originally free leaves eventually forming the marginal teeth of the common 
basal portion. Applying the term Sepal to a calycine, Petal to a coroUine leaf, 
a calyx consisting of coherent leaves is gamosepalous or synsepalous, a corolla con- 
sisting of coherent leaves gamopetalous or sympetalous ; if the leaves of the perianth- 
whorl are not coherent, but free, this is expressed by the terms eleiitherosepalous 
or aposepalous, and eleutheropetalous or apopetalous^. When there is only one 
perianth- whorl, and it is desired to state whether it consists of coherent or of free 
leaves, the terms gamophyllous or symphyllous and eleutherophy lions or apophyllous 
may be used. It sometimes happens moreover that two perianth-whorls coalesce 
into one, so that, for example, two alternating trimerous whorls have united into a 
six-toothed tube (as in Hyacinthus^ Muscan, &c.). 
If the leaves of the outer and inner whorls are free (not coherent), and if 
the distinction between calyx and corolla is clearly marked, then, in addition to 
the structural distinctions already named, other differences of form are also usually 
to be observed. The sepals have generally a broader base, are sessile, usually of 
very simple outline and pointed at the apex ; the petals have mostly a narrower 
base, their upper portion is often very broad, and a distinction is not unfrequently 
apparent of claw {unguis) and blade (lamina), and the lamina is often divided or 
otherwise segmented. At the point where the lamina bends back from the unguis, 
ligular structures are often formed on the inner or upper side, which, when treating 
the flower as a whole, are comprised under the term Coro?ia, as in Lychnis 
(Fig. 361), Saponaria, Nerium, Hydrophylleae, &c. When the corolla itself is 
^ The terms ' polysepalous ' and ' polypetalous ' are objectionable, since these terms do not 
express the contrast correctly ; still more so are ' monosepalous ' and ' monopetalous,' as applied to 
the coherent whorls, because they have no reference to the true nature of the phenomenon. 
Fig. 361.— Longitudinal section throuj^h the flower of Lychnis flos-Jovis ; y the elongated portion of the axis 
(anthophore) between calyx and corolla ; x ligule of the petals or corona. 
