Dahlia, dal'ya, a genus of flowering herbs, remotely akin to sunflowers and asters, and closely related to the coreopsis and beggar's tick. There are several wild species, native to Mexico. The dahlia was named by Linnaeus for his student, Dr. Dahl. The original plant is said to be eight feet high, with a single row of dull scarlet rays and a yellow center. Florists now claim 2,000 varieties, mostly double, in every hue known to the horticultural show. The dahlia is raised generally from spindle-shaped tubers, of which the plant produces a cluster late in autumn. They need the same care as potatoes. The dahlia has been considered a coarse flower, but of late it is sharing the interest which has been shown in the chrysanthemum. One of the popular new forms has flowers not unlike a cactus, and is called the cactus variety.