Which of the following statements is not correct?

Pollen grains of many species cannot germinate on the stigma of a flower as the pollen grains from other species will not be accepted.

Most pollen grains are monosiphonous, i.e., only a single pollen tube emerges from each pollen grain; others, like those of the Malvaceae, Cucurbitaceae and Campanulaceae, are polysiphonous. In Althaea rosea 10 tubes, and in Malva neglecta even 14 tubes, are known to come out from the same pollen grain. Eventually, however, only one of them makes further progress.