Potamon fluviatile Potamon fluviatile Potamon fluviatile is a freshwater crab found in or near wooded streams, rivers and lakes in Southern Europe. It is an omnivore with broad ecological tolerances, and adults typically reach in size during their 10–12 year lifespan. They inhabit burrows and are aggressive, apparently outcompeting native crayfish. "P. fluviatile" has been harvested for food since classical antiquity, and is now threatened by overexploitation. Many of the island populations are particularly vulnerable, and the Maltese subspecies has become a conservation icon. A population in Rome may have been brought there before the founding of the Roman Empire. Adult "Potamon
Equisetum fluviatile ancient Chinese to treat superficial visual obstructions. Rootstocks and stems are sometimes eaten by waterfowl. Horsetails absorb heavy metals from the soil, and are often used in bioassays for metals. According to Carl Linnaeus, reindeer, which refuse ordinary hay, will eat this horsetail, which is juicy, and that it is cut as fodder in the north of Sweden for cows, with a view to increasing their milk yield, but that horses will not touch it. Equisetum fluviatile Equisetum fluviatile, the water horsetail or swamp horsetail, is a vascular plant that commonly grows in dense colonies along freshwater shorelines or in