Chrysanthemum: A plant genus of the family ASTERACEAE. The common names of daisy or marguerite are easily confused with other plants. Some species in this genus have been reclassified to TANACETUM.Chrysanthemum cinerariifolium: A plant species of the genus CHRYSANTHEMUM, family ASTERACEAE. The flowers contain PYRETHRINS, cinerolones, and chrysanthemines which are powerful contact insecticides. Most in the old Pyrethrum genus are reclassified to TANACETUM; some to other ASTERACEAE genera.Viroids: A group of pathogens comprising the smallest known agents of infectious disease. They are unencapsulated and are capable of replicating autonomously in susceptible cells. Positively identified viroids composed of single-stranded RNA have been isolated from higher plants, but the existence of DNA viroids pathogenic to animals is suspected.Carlavirus: A genus of RNA plant viruses in the family FLEXIVIRIDAE, containing slightly flexuous filaments, often transmitted by aphids in a non-persistent manner. Carnation latent virus is the type species.Asteraceae: A large plant family of the order Asterales, subclass Asteridae, class Magnoliopsida. The family is also known as Compositae. Flower petals are joined near the base and stamens alternate with the corolla lobes. The common name of "daisy" refers to several genera of this family including Aster; CHRYSANTHEMUM; RUDBECKIA; TANACETUM.Mesophyll Cells: Large and highly vacuolated cells possessing many chloroplasts occuring in the interior cross-section of leaves, juxtaposed between the epidermal layers.Flowers: The reproductive organs of plants.