=Dialysis of the corolla= is likewise of frequent occurrence, either partially or to such an extent as to render the corolla truly polypetalous. Among _Labiatae_ the upper lip of the corolla may be often met with partially cleft, as it is constantly in _Phlomis biloba_, or more markedly among the _Lobeliaceae_. In the _Compositae_, a similar separation of the petals is not infrequent, thus showing frequent transitional stages between the labiatifloral and tubulifloral divisions respectively. The ligulate corollas also may often be found in Chrysanthemums, Dahlias, &c., more or less deeply divided into their component parts. A more complete separation occurs not unfrequently in _Campanula_, _Rhododendron_, _Phlox_, _&c._ Figs. 30 and 31 illustrate dialysis of the corolla; the first in _Correa_, the second in _Campanula_. [Illustration: FIG. 31.--Dialysis of the corolla in _Campanula sp._, after De Candolle.] In the last-named genus, _C. rotundifolia_ has been found with polypetalous flowers in a wild state in the mountains of Canton Neufchatel, Switzerland, and gave rise to the creation of a new genus. This form is now introduced into gardens. It must be remembered that in some genera, where this separation of the petals has been met with, there are species in which a similar isolation occurs normally, as in _Rhododendron_. _R. linearilobum_, a Japanese species, offers a good illustration of this. The following list contains the names of the genera in which this separation of the petals of an ordinarily gamopetalous flower takes place most frequently. Correa. Campanula! sp. pl. Polemonium. Phlox! Coboea! Rhododendron! Erica! Rhodora. Azalea! Compositae! sp. pl. Lonicera! Convolvulus! Pharbitis. Antirrhinum! Verbascum! Mimulus. Digitalis! Orobanche. Solanum. Nicotiana. Gentiana! Anagallis. Primula! Lamium! Convallaria! Lilium! Colchicum! &c. &c. This list does not include those very numerous cases in which this change is associated with more or less complete frondescence or leafy condition of the petals. =Dialysis of the stamens.=--A similar isolation of the stamens occurs occasionally; for instance, when Mallows (_Malvaceae_) become double, one of the first stages of the process is often the disjunction of the stamens, and a similar dissociation occurs in _Leguminosae_ and _Compositae_, as in _Tragopogon_, as related by Kirschleger, in _Hypochaeris_ by Wigand, and in _Coreopsis_ by Schlechtendal. =Dialysis of the carpels.=--In the case of the carpels this disunion is more frequent than in the stamens. M. Seringe[78] figures carpels of _Diplotaxis tenuifolia_ more or less completely separated one from the other; indeed, this separation is very common amongst _Cruciferae_ and _Umbelliferae_.