What is actually hydrophyte?

Why is the stomata present on the upper side of a hydrophyte and lower in the xerophyte?

• Answer:

  The stomatas are present on the upper side of a hydrophyte because the hydrophyte lives in water and therefore it gets excess water, so to improve the loss of water through transpiration the stomatas are present on the upper side of the leaf of a hydrophyte. Water has to be lost because the plant can sink as water will make it less dense and heavy. Xerophytes have stomata on the lower side because they do not get excess water but they get less than what they need, hence the stomatas are present on the lower side so that less water is lost. Secondly, they live in desets and there will be more evaporation as desert is very hot.