This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Annuals or perennials with pinnate leaves and solitary flower-heads. Receptacle furnished with linear acute coloured bracteoles, equalling or exceeding the florets. Achenes angular, largest in the middle, crowned with three or four rigid bristles. Koouos signifies beautiful or perfect.
1. C. bipinnatus (fig. 134). - An elegant annual about 2 feet high. Flowers rose or purple with a yellow eye, appearing late in Summer. Mexico.
Fig. 134. Cosmos bipinnatus. (1/4 nat. size.)
2. C. diversifolius, syn. Dahlia Zimapani. - A tuberous-rooted dwarf perennial with Dahlia-like foliage and uniform dark purple flowers.