COROLLA

(Lat. corolla, a ^ar/awd.) That envelope of a flower which is placed next within the calyx. It is usually more richly coloured and larger than the latter, but is extremely variable in this respect. Owing to its being in many plants one of the most striking parts of the flower, it is much employed by botanists in their systematical arrangements, and by the French school has been taken as the means of forming fundamental characters of the subcla es in the great Dicotyledonous division; but there is no doubt that its importance for this purpose has been much overrated. Theoretically considered, the corolla is composed of modified leaves, with the ordinary organization of which its parts or petals correspond as much as can be expected of rudimentary organs; its physiological action is to absorb oxygen, without decomposing carbonic acid, in which respect it agrees with leaves in their morbid state in the autumn. The corolla has been described by Lamarck as a diseased state of the foliage. [s. 296]