Developmental morphology of the androecium and gynoecium in Ruppia maritima L.: considerations for pollination

Using scanning electron microscopy and thin sectioning, the functional morphology of the gynoecium, anthers, and pollen grains of Ruppia maritima, widgeon grass, were studied. The funnel-like arrangement of the carpels directing pollen to the stigmatic regions, the buoyancy offered by the presence of stomates and underlying spongy tissue in the carpellary outgrowth, the boomerang-like morphology of the pollen grains which facilitates their aggregation, and the sheath enclosing the anther, are examined from the perspective of this specialized, hydrophilous pollination system..