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.
Or, to put it another way, quasars are an extreme kind of active galactic nuclei, which are the centers of active galaxies that spew out huge amounts of excess energy. Such huge amounts of energy are believed to be released as matter swirls around and eventually falls into a supermassive black hole at the center of the quasar.