Gomphonema acuminatum diatom

From a R.I. Firth type slide

This is a common smaller diatom which is found in freshwater and slightly brackish water. It dwells on the bottom of bodies of water, attached to rocks and other sedimentary material. It forms branched mucilagenis stalks. The frustule is characterized by a Clavate(club-like) valves, tumid(bulging) at the center with two marginal constrictions with a broad headpole that becomes apiculate (pointed). The areolae are slightly C-shaped or kidney-shaped, and although the areolae can be resolved with a light microscope, and are uniseriate(one striae contains one row of areolae), they are too small to reveal their shape except with an electron microscope.