In his arrangement the last subdivision disappears, and the Dicotyledons fall into two groups, a larger containing those in which both calyx and corolla are present in the flower, and a smaller, Monochlamydeae, representing the Apetalae and Diclines Irregulares of Jussieu.
The flowers are large, yellow, scented and a little drooping, with a corolla deeply cleft into six lobes and a bell-shaped corona which is crisped at the margin; they appear in March or April.
The corolla has from five to nine petals, cohering at the base.
In Amorpha and Afzelia the corolla is reduced to a single petal, and in some other Leguminous plants it is entirely wanting.
The branches and corolla are purple, the fruit woolly.
A gamopetalous corolla falls off in one piece; but sometimes the base of the corolla remains persistent, as in Rhinanthus and Orobanche.
Thus, in many Caryophyllaceae, as Polycarpon and Holosteum, while the calyx and corolla are pentamerous, there are only three or four stamens and three carpels; in Impatiens Noli-me-tangere the calyx is composed of three parts, while the other verticils have five; in labiate flowers there are five parts of the calyx and corolla, and only four stamens; and in Tropaeolum pentaphyllum there are five sepals, two petals, eight stamens and three carpels.
Many plants produce, in addition to ordinary open flowers, so-called cleistogamous flowers, which remain permanently closed but which notwithstanding produce fruit; in these the corolla is inconspicuous or absent and the pollen grows from the anther on to the stigma of the same flower.
The scales around the throat of the corolla protect the pollen and honey from wet or undesirable visitors, and by their difference in colour from the corolla-lobes, as in the yellow eye of forget-me-not, may serve to indicate the position of the honey.
Sometimes, as usually in monocotyledons, the calyx and corolla are similar; in such cases the term perianth, or perigone, is applied.