What type of placentation is found in sunflower?

The arrangement of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and describe various types of placentations in flowers as seen in $T.S.$ or $V.S$.

$\underline{G}$ and $\overline{G}$ indicate respectively $:-$

In $Hibiscus$ $rosa-sinensis$,there is an additional floral whorl known as:

Vexillary aestivation is a characteristic feature of ...... flowers.

Axile placentation is observed in