A Psilon is a unit of length that is equal to 44 manly strides or, less precisely, 0.025 miles

Miles

Miles is the plural of mile.Miles may also refer to:- People :*Miles Brothers, American cinema pioneers* Miles ** Miles Browning, World War II admiral** Miles Davis, jazz trumpet player** Miles Austin, Dallas Cowboys wide receiver...

 (a quarter of a tenth of a mile) or 40 meters. The Psilon is best known as the official unit of measurement during the censusing of plants in the genus Silene (see Silene

Silene

Silene is a genus of flowering plants in the family Caryophyllaceae. Common names include campion and catchfly....

) in a metapopulation

Metapopulation

A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1970 to describe a model of population dynamics of insect pests in agricultural fields, but the idea has been most...

 surrounding Mountain Lake Biological Station in Giles County, Virginia

Giles County, Virginia

As of the census of 2000, there were 16,657 people, 6,994 households, and 4,888 families residing in the county. The population density was 47 people per square mile . There were 7,732 housing units at an average density of 22 per square mile...

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Etymology: Derived from the Latin Silene.