Centaurea Cyanus: hardy, 3 ft., blue, purple, pink or white; showy.
Centranthus macrosiphon: hardy, 1½ to 2 ft., rosy-carmine.
Centranthus ruber (known as Pretty Betsy and Red Valerian): hardy, 2 to 3 ft., red.
Chrysanthemum carinatum: a charming half-hardy annual, 2 to 3 ft. high, with several varieties, of which C. Burridgeanum with zones of white, crimson and yellow is best.
C. coronarium, a yellow-flowered species requires similar treatment.
Clarkia pulchella: hardy, 1½ ft., rosy-purple; some varieties very handsome.
Collinsia bicolor: hardy, 1½ ft., white and purple; pretty.
Collinsia verna: hardy, 1 ft., white and azure; sow as soon as ripe.
Convolvulus tricolor atroviolacea: hardy, 1 ft., white, blue and yellow. This is the Convolvulus minor of gardens.
Cosmos bipinnatus: half-hardy, 3 ft., rose, purple, white; requires sunny spots.