Yes it does. wolfia nan azzola will take food from lemna.
Wolfia and Lemna are the smallest angiosperms
The flowers of some Wolfia species are as small as 1/70th inch while A. minutissimum has flowers about 1.5 mm (about 1/17th inch) in length.
Floating Wolfia Angansta, dcukweed family
No because in photosynthesis (the production of food) Light, soil, and carbon dioxide are needed in the process to make food. Plants cannot grow in pure water. They need food and air even if it is dissolved in water like for algae or sea weed and other underwater plants. A number of hydrophytic plants like spirogyra, chara (algae) and Pistia, Lemna, wolfia etc (angiosperms) can be grown in the pond water. Growing plants in water scientifically is called hydrophonics.