Are Arenaria and Sciadopitys verticillata part of the same family?
Sciadopitys Sciadopitys verticillata, koyamaki, or Japanese umbrella-pine, is a unique conifer endemic to Japan. It is the sole member of the family Sciadopityaceae and genus Sciadopitys, a living fossil with no close relatives, and known in the fossil record for about 230 million years.
A. arenaria An abbreviation of a species name. In binomial nomenclature the name of a species is always the name of the genus to which the species belongs, followed by the species name (also called the species epithet). In "A. arenaria" the genus name has been abbreviated to "A." and the species has been spelled out in full. In a document that uses this abbreviation it should always be clear from the context which genus name has been abbreviated.