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.
Tall biennials or perennials with simple alternate and racemose simple or compound inflorescence. Flowers showy, white, yellow, violet, purple or red. Calyx 5-lobed. Corolla rotate, with 5 nearly equal segments. Stamens 5. All or only the 3 posterior filaments bearded. Capsule 2-valved, many-seeded. The species are numerous, and there are several forms known to be natural hybrids. They are confined to the north temperate and warm regions of the Old World. The generic name is an altered form of the Latin Barbascum.
There are five or six indigenous species popularly known by the name of Mullein. V. Thdpsas is a tall coarse biennial with densely woolly decurrent leaves and dense spikes of yellow flowers. V. Lychnltis has small white flowers; V. Blattaria is nearly glabrous, with a glandular branched inflorescence of large yellow flowers with purple-bearded filaments; and V. nigrum is pubescent, with angular almost simple stems and smaller yellow flowers with purple bearded filaments.
1. V. Phoeniceum (fig. 185). - A slender glabrous perennial about 3 or
4 feet high. Flowers violet, rose, or nearly white. A native of the South of Europe, flowering all the Summer.
Fig. 185. Verbascum Phoeniceum. (1/4 nat. size.)
V. pyramidatum, V. undulatum, and V. acuminatum are other large-growing yellow-flowered species.