Egeria (plant) particularly in Europe, fast-growing, adaptable plants such as "Egeria" can spread quickly and cause major damage to native plants and wildlife. Egeria (plant) Egeria is a genus of three species of aquatic plants in the family Hydrocharitaceae described as a genus in 1849. native to warm-temperate South America. The genus was formerly included in the related genus "Elodea", from which it differs in having the leaves in whorls of four or more, not three, and in having more conspicuous flowers with larger (particularly broader) petals. "Egeria" is found in many temperate and subtropical regions throughout the world as an introduced,
How many angels can dance on the head of a pin? How many angels can dance on the head of a pin? The question "How many angels can dance on the head of a pin?" (alternatively ""How many angels can stand on the "point" of a pin?"") is a reductio ad absurdum of medieval scholasticism in general, and its angelology in particular, as represented by figures such as Duns Scotus and Thomas Aquinas. It is first recorded in the 17th century, in the context of Protestant apologetics. The question has also been linked to the fall of Constantinople, with the imagery of scholars debating about minutiae while the Turks besieged the