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.
This genus comprises a few species separated from Pentste-mon on account of the seeds being winged, the barren stamen shorter than the others, and the inflorescence a close bracteated spike. The species are all North and Central American, is equivalent to tortoise, and is applied to this genus from the resemblance of the inflated corolla to that animal. Ch. barbata, Ch. gentianoides, Ch. centranthifolia, Ch. cam-panulata, and Ch, speciosa are true Pentstemons.
1. Ch. glabra, syn. Ch. purpurea and Ch. obliqua. - An erect glabrous perennial about 2 feet high. Leaves nearly sessile, lanceolate, acuminate, serrate. Flowers white, rose or purple, nearly sessile; bracts foliaceous, imbricated. This has several different popular names in America; as Turtle-head, Snake-head, Shell-flower, Balmony, etc.
2. Ch. major, syn. Ch. Lyonsii. - A very handsome robust species, 3 to 4 feet high, with broadly cordate serrulate-ciliate slightly hairy leaves and large purple flowers.