Pollination is a strange thing to us humans. Whereas we accomplish reproduction by simply locating a member of the opposite sex and copulating, plants have to utilize a third party. The most familiar cases include insects like bees and butterflies. More unique examples include birds, bats, and even lizards. Many plants forego the need of an animal and instead rely on wind to broadcast copious amounts of pollen into the air in hopes that it will randomly bump into a receptive female organ. This has worked quite well for terrestrial plants but what about their aquatic relatives? Water proves to be quite an obstacle for the methods mentioned above. Some species get around this by thrusting their flowers above the water surface but others don’t bother. One genus in particular has evolved quite a novel way of achieving sexual reproduction without having to leave its aquatic environment in any way. 

Meet the Vallisnerias. Commonly referred to as tape grasses, this genus of aquatic plants has been made famous the world over by their use in the aquarium trade. In the wild they grow submerged with their long, grass-like leaves dancing up into the water column. Where they are native, tape grasses function as an important component of aquatic ecology. Everything from fish and crustaceans all the way up to manatees utilize tape grass beds. They stabilize stream beds and shorelines and even act as water filters. 

All this is quite nice but, to me, the most interesting aspect of Vallisneria ecology is their reproductive strategy. Whereas they will reproduce vegetatively by throwing out runners, it is their method of sexual reproduction that boggles the mind. Vallisneria produce either male or female flowers. The female flowers are born on long stalks that reach up to the water surface. Once there they stop growing and start waiting. Because of their positioning, water tension causes a slight depression around the flowers at the surface. The depression resembles a little dimple with a tiny white flower in the center.

Male flowers are quite different. Much smaller than the female flowers, a single inflorescence can contain thousands of them. As they mature underwater, the male flowers break off from the inflorescence and float to the surface. Like wind pollinated terrestrial plants, Vallisneria use water currents to disperse their pollen. Once at the surface, the tiny male flowers float around like little pollen-filled rafts. If a male flower floats near the dimple created by a female flower, it will slide down into the depression where it comes into contact with the female flowers thus, pollination is achieved. Once pollinated, hormonal changes signal the stem of the female flower to begin to coil up like a spring, drawing the developing seeds safely underwater where they will mature. Eventually hundreds of seeds are released into the water currents.


Photo Credits: eyeweed (

Lookie!!! Guess who has a 5.5 gallon set up ready for her koi betta baby that is on hold? Yeeeeeeah! I got a Cobomba, a Vallisneria (i might get another) and a bunch of dwarf hair grass all planted with pretreated flourite. I have a Biomaxx nano and a 50 watt heater. Tomorrow I am picking up hidey place for him, a thermometer cuz i forgot and food cuz I forgot that as well. I wont be picking up Koi Boy till saturday or sunday. His tank mates are a Dwarf frog (no name yet) and an Assassin Snail (Ezio) for the snails that will be aboard the Crypts that the amazing Gar-a-ash is sending me! I cant wait to get them! I just cant believe I own a koi betta!!