Cistus, with its many hybrids and cultivars, is commonly encountered as a garden flower. The common name rockrose is applied to the species, a name also shared by the related genera Halimium, Helianthemum and Tuberaria, all in the family Cistaceae. The common name gum cistus is applied to resin-bearing species, especially C. ladanifer.
Quasars are part of a class of objects known as active galactic nuclei (AGN). Other classes include Seyfert galaxies and blazars. All three require supermassive black holes to power them.
Stingrays are any of a number of flat-bodied rays noted for the long, sharp, venomous spines on their tails. They are cartilaginous fish and are related to sharks. Stingrays sometimes are placed in a single family, Dasyatidae, but often are separated into two families-Dasyatidae and Urolophidae.