Pond Weed
Potamogeton sp.
Photographed on ponds used for aquaculture, Eldoret, Kenya. July 2014.
From Wikipedia: In many species, all the leaves are submerged, and in these cases, they are typically thin and translucent. Some species, especially in ponds and very slow-moving waters, have floating leaves which tend to be more leathery. Diagnostic of most species of Potamogeton is the presence of a delicate membranous sheathing scale at the leaf axil. This may be wholly attached, partly attached, or free of the leaf, and it may have inrolled margins or appear as a tube. The flowers, which are often overlooked, are composed of four rounded segments borne in a spike. The genus name means "river neighbor", originating from the Greek potamos (river) and geiton (neighbor).