The Pollination of the Ribbon Weed

Methods of Pollination

• Plants have devised many avenues for sexual reproduction to maximize their chances at successful propagation. Many land plants rely on an ancient ally, wind, to disseminate pollen. This is true for the trees called gymnosperms, which include all conifers, as well as for many of the flowering plants, or angiosperms. More specialized styles of pollination involve animals, from insects to the huge fruit bats called flying foxes. So intricate has the evolutionary dance been between plants and their animal pollinators that some species exist in exclusive partnership. Various species of yucca shrubs in the U.S. Southwest, for example, have their own specific variety of yucca moth to pollinate them.

Ribbon Weed

• Ribbon weed is one of the common names for a number of species of aquatic herb in the genus Vallisneria. They are also sometimes called eelgrasses, though they do not belong to the true grass family, and that name is also used for other, unrelated plant groups. Widely distributed in the tropics and temperate regions, the genus includes certain species such as Vallisneria spiralis and Vallisneria nana that are popular in home aquariums.

Ribbon Weed Pollination

• Ribbon weed employs a style of pollination that relies both on water and wind. Female flowers extend from fixed roots to the surface on spiral stalks called pedicels. The tiny male flowers are released from structures in the leaf sheaths and float to the surface, where they become “pollen boats.” Sloughed along by breeze and current, some will come in contact with the female flowers and thus facilitate pollination. Anything can disrupt the random journey of the male flower to its ideal endpoint at the female. Fish will often consume the pollen boats, for example. The fertilized female flower will eventually produce a fruit. The structure is slender and cylindrical, full of seeds and up to 3 inches long.

Other Aquatic Plants

• The basic pollination strategy of the ribbon weed is somewhat mirrored in duckweeds -- members of the family Lemnaceae, most minuscule of angiosperms -- where flowers are shoved together by wind. In true eelgrasses, male pollen grains are washed against the specialized reproductive structures called stigmas in the female flowers, wrapping around them in the buffeting of ocean currents.