I'm feeling lazy (and the Life Science Library is closed just now anyhow),
so I wondered if anyone on the list was familiar with:

  Nielsen, E. Steemann.  _Photosynthesis of aquatic plants with special
    reference to the carbon-sources._  Kobenhavn 1947.

  Gessner, Fritz.  _Hydrobotanik; die physiologischen Grundlagen der
    Pflanzenverbreitung im Wasser._  Berlin 1955-1959.

For that matter any more recent bibliography on this subject would be
appreciated.  Thanks!

  --Martin Harriman
    martin-h at mail_utexas.edu