These can include wind, water, insects and birds. Grasses and gymnosperms use wind pollination. These plants typically do not have showy floral parts, fragrances, or nectar . Their stigmas are large, and their stamens are well-exposed. Each flower has only one ovary with a single ovule, but many flowers are packed into each inflorescence.
Some aquatic plants rely on water for the transfer of pollen.
If they encounter a pistilate flower, they are drawn into the flower by way of a channel created by the surface tension of the water around the flower, and can slide down into a receptive stigma. Insects are the most common animal pollinators, and bees are the most common insect pollinators. Bees are most often attracted to red flower color, and gather both nectar and pollen. Some flowers have strong scents or nectar guides that consist of a target created by UV reflectance, with darker shades toward the center of the flower, or visible patterns that insects can recognize, remember, and communicate. Some mammals such as bats act as pollinators of light colored, strongly fruity scented flowers that open at night, and birds, especially hummingbirds, pollinate the flowers from which they collect nectar.