 Many trees and all grasses and sedges are wind-pollinated, as such they have no need for any flowers.Plants have a number of different means to attract pollinators including color, scent, heat, nectar glands, edible pollen and flower shape.Along with modifications involving the above structures two other conditions play a very important role in the sexual reproduction of flowering plants, the first is the timing of flowering and the other is the size or number of flowers produced.