Chrysanthemum
2 of the 6 encyclopedias on this shelf carry an entry for Chrysanthemum. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
kris-an the-mum, a flowering herb belonging to the aster family. The name is Greek, meaning golden flower, having reference to the yellow straps of the corolla. The original type had but a single row of strap-shaped flowers. The double varieties have been obtained by causing the small, five-pointed corollas of the disk flower to develop into straps. The florists of China and Japan excel in the cultivation of this flower. Our large flowered varieties are obtained from a blending of two species that grow wild in China and Japan. Although the original color was yellow, the florist now produces white, pink, bronze, and crimson, as well as saffron-colored varieties. Botanically the common ox-eye daisy, or white-weed, and the marguerite flower are chrysanthemums. Chuck-will's-widow, a bird of the goat-sucker family, allied to the whip-poor-will, but larger. Its notes and habits are like those of the whip-poor-will. It feeds on the wing by catching insects. It has an enormous mouth. Chapman is authority for the occurrence of humming birds and sparrows in its stomach, which he kindly covers with the mantle of charity by suggesting that these small birds may have been mistaken for large moths. Two dull white eggs, with lilac markings, are laid on the ground or on leaves in thickets and groves. See Whip-Poor-Will
Collier's New Encyclopedia (1921)
a herbaceous or slightly shrubby plants, belonging to the corymbiferous group of the order Composite. The family is represented in the United States by the well-known ox-eye daisy, Chrysanthemum leucanthemum, and the corn marigold, C. Segetum, besides which many varieties have been introduced from other countries and are cultivated here. C. Sinense is the plant commonly known as the Chrysanthemum, and so much prized for its flowering in November and December.
What Has Changed in the Last Century
Both accounts casually call the ox-eye daisy and corn marigold chrysanthemums, and botanists of 1910 and 1921 were right by the rules of their day. Since then the genus has been broken up: the ox-eye daisy is now Leucanthemum vulgare and the corn marigold Glebionis segetum, while the florist's plant Collier's called C. sinense is treated as the hybrid Chrysanthemum x morifolium. A long nomenclatural quarrel over which species should anchor the name was settled only in the 1990s, in favour of keeping Chrysanthemum for the garden mums. Collier's prized the flower because it bloomed "in November and December"; growers now control flowering by manipulating day length, so pot mums are sold in every month of the year.
Written for this edition, 2026.