Potamon fluviatile northeastern Greece. In mainland Greece, "P. fluviatile" is found in the drainages of the Axios, Thyamis, Aheron and Arachthos, Pineiós, Piros-Tethreas, Pamisos and Evrotas rivers. In the Ionian Islands, "P. fluviatile" is known to occur at only one site on Corfu, as well as on Kefalonia, Lefkada and Zakynthos. In the Aegean Islands, it is found on Skiathos and Skopelos (Sporades), on Euboea and Skyros, and at a single site on Andros in the Cyclades. "Potamon fluviatile" is at the western distributional limit of the genus "Potamon". Other species in the genus occur through Eastern Europe and the Middle East,
Blechnum fluviatile a short trunk central to a surrounding colony. The hardy "B. fluviatile" requires moist, shaded conditions for optimal growth. A small ground fern, the "B. fluviatile" is native to New Zealand and southeast Australia, a syntype common throughout the country in damp, shady areas in acidic, moist and boggy soil, beside streams in forest areas. This fern species occurs throughout much of New Zealand's forests, including much of the forested area of North Island; west, north and south coasts of South Island; and Stewart Island/Rakiura; moreover, it occurs in parts of the coastal forests of southeast Australia. Example understory flora