In many flowers the petals are joined, at least at the base, so that the corolla is a tube - in red clover, for example Cross- pollination The transfer of pollen from an anther (pollen sac) of one plant to a stigma (tip of the female part of a flower) of another and genetically different plant.
(the petals; are joined; L:at least at the base; L:In many flowers) (the corolla; is; a tube - in red clover)
the petals the corolla
are joined is
L:at least at the base L:In many flowers
a tube - in red clover