Malus Malus Malus ( or ) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple ("M. pumila" syn. "M. domestica" ) – also known as the eating apple, cooking apple, or culinary apple. It is dealt with under Apple. The other species are generally known as crabapples, crab apples, or wild apples. The genus is native to the temperate zone of the Northern Hemisphere. Apple trees are typically tall at maturity, with a dense, twiggy crown. The leaves are long, alternate, simple, with a serrated margin. The flowers
Étienne-Louis Malus Étienne-Louis Malus Étienne-Louis Malus (; ; 23 July 1775 – 24 February 1812) was a French officer, engineer, physicist, and mathematician. Malus was born in Paris, France. He participated in Napoleon's expedition into Egypt (1798 to 1801) and was a member of the mathematics section of the Institut d'Égypte. Malus became a member of the Académie des Sciences in 1810. In 1810 the Royal Society of London awarded him the Rumford Medal. His mathematical work was almost entirely concerned with the study of light. He studied geometric systems called "ray systems", closely connected to Julius Plücker's "line geometry". He conducted