what kind of flora existed during the said period?
Flowering plants, Mesozoic gymnosperms, Gleicheniales
Cretaceous
Flowering plants (angiosperms) spread during this period, although they did not become predominant until the Campanian Age. Their evolution was aided by the appearance of bees; in fact, the development of angiosperms and insects is a good example of coevolution. The first representatives of many leafy trees, including figs, planes and magnolias, appeared in the Cretaceous.

At the same time, some earlier Mesozoic gymnosperms continued to thrive, pehuenes (monkey puzzle trees, "Araucaria") and other conifers being notably plentiful and widespread. Some fern orders, such as Gleicheniales, appeared as early in the fossil record as the Cretaceous and achieved an early broad distribution. Gymnosperm taxa like Bennettitales and Hirmeriella died out before the end of the period.
what is psittacosaurus? It is a genus of extinct ceratopsian dinosaur from the Early Cretaceous
wiki:1534494
Cretaceous [SEP] Flora
Flowering plants (angiosperms) spread during this period, although they did not become predominant until the Campanian Age. Their evolution was aided by the appearance of bees; in fact, the development of angiosperms and insects is a good example of coevolution. The first representatives of many leafy trees, including figs, planes and magnolias, appeared in the Cretaceous. At the same time, some earlier Mesozoic gymnosperms continued to thrive, pehuenes (monkey puzzle trees, "Araucaria") and other conifers being notably plentiful and widespread. Some fern orders, such as Gleicheniales, appeared as early in the fossil record as the Cretaceous and achieved an early broad distribution.