|MadSci Network: Botany|
I'm afraid that your question is a little hard to answer. If when you use the term "seafloor" you mean the deep parts of the ocean floor, then I'm afraid there would not be any plants growing there because they require light. At those depths, there is no light. There are many species of bacteria and perhaps some algae in the shallower parts on the continental shelf (before the ocean slopes off). In order to live at great depths you must be able to be a scavenger and eat whatever rains down from above.
Sorry I can't be of more help.
Warren Currie - Department of Zoology
University of Guelph
David Hershey adds the following:
In the five kingdom system of classification with algae in Kingdom Protista, fingi in Kingdom Fungi and bacteria in Kingdom Monera, the only members of the Plant Kingdom in the oceans are angiosperms known as seagrasses. Seagrasses live in shallow coastal ocean waters. There are about 58 species in 12 genera. Some species include eelgrass (genus Zostera) and widgeon grass (genus Ruppia) in the Atlantic and north Pacific. In tropical waters, there are turtle grass (genus Thalassia), shoal grass (genus Halodule) and manatee grass (genus Syringonium).
The Western Australian Seagrass Web Page
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