What is "hesperis matronalis"

Damewort \Dame"wort`\, n. (Bot.) A cruciferrous plant ( Hesperis matronalis), remarkable for its fragrance, especially toward the close of the day; -- called also rocket and dame's violet.
--Loudon.

Hesperis matronalis is a herbaceous plant species in the mustard family, Brassicaceae. It has numerous common names, including dame's rocket, damask violet, dame's-violet, dames-wort, dame's gilliflower, night-scented gilliflower, queen's gilliflower, rogue's gilliflower, summer lilac, sweet rocket, mother-of-the-evening and winter gilliflower. Plants are biennials or short-lived perennials, native to Eurasia and cultivated in many other areas of the world for their attractive, spring-blooming flowers. In some of those areas, it has escaped cultivation and become a weed species. The genus name Hesperis is Greek for evening, and the name was probably given because the scent of the flowers becomes more conspicuous towards evening.