They have also always an involucrum below the298 calyx, but this involucrum differs in the different genera.
In the genus Malva, the involucrum consists of three leaflets, which in the common Mallow (Malva sylvestris) are oblong.
The involucrum is formed also of one piece, and the three leaves are laid one over the other as in the annexed flower.
The leaves are triternate, divisions deeply cut and acute; the leaves of the involucrum are stalked, trifid, and deeply cut.
It belongs to that section of its numerous genus having an involucrum of stalked leaflets.
Said involucrum is composed of numerous small leaves, a distinguishing trait from its nearest relative genus Rudbeckia.
As the seeds ripen, the involucrum falls off, but the large loose-looking calyx remains on.
A little later the involucrum becomes developed, and is no unimportant feature.
involucrum in·vo·lu·crum (ĭn'və-lōō'krəm)
n. pl. in·vo·lu·cra (-krə)
An enveloping sheath or membrane, such as the sheath of new bone that forms around a sequestrum.