Which of these hve stomata on the upper surface?

Question

grass, ipil-ipil, lotus and sampaguita

Answer 1

Well, Lotus will definitely have stomata on the upper surface.  Stomata are small pores that allow a plant to bring in carbon dioxide.  Water vapor also leaves through these pores, so most plants put them on the under surface of the leaves so they don't get exposed to direct sun, which would increase water loss.

But, because Lotus has leaves that sit on the water surface, the underside is often in the water and having the stomata there would be of no use.  Also, since they live in water, Lotus aren't as susceptible to drying out from excessive water loss through stomata.

Many grass species, because they are curled with the lower surface more exposed to the sun, also put more stomata on their upper surface.

I've never looked at ipil-ipil or sampaguita leaves, so I don't know where they put stomata, but since they aren't grasses or water plants, they probably have most of their stomata on the underside.