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.
North American herbaceous perennial plants with simple or pinnate opposite or alternate leaves and showy flower-heads of brightly coloured florets. Receptacle conical, with chaffy scales at the base of the florets. Achenes quadrangular, with a minute pappus or none. The species number from fifteen to twenty, and all are hardy or nearly so. Named after a Swedish botanist.
1. R. purpurea, syn. Echinacea serotina, etc. (fig. 130). - A plant about a yard high, rough to the touch, with ovate-lanceolate obscurely dentate leaves and large flower-heads nearly 4 inches in diameter. The prominent disk is dark brown, and the ray bright reddish purple. R. intermedia, with rather broader more deeply coloured and spreading not deflexed more numerous ray-florets, is said to be an improved variety of this species, or perhaps a hybrid between it and some other. A native of the southern United States, flowering in Summer.
Fig. 130. Rudbeckia purpurea. (1/6 nat. size.)
Fig. 131. Rudbeckia Drumraondii. (1/3 nat. size.)
R. asperrima and R. angustifolia are closely allied species : the former with pale rose flowers, in which the florets are narrow, numerous, and toothed at the tip; and the latter with narrow leaves and purplish flowers.
2. R. Drummondii, syn. Lepachys columnaris, Obeliscaria pulcherrima, etc. (fig. 131). - A very showy species in some of its varieties. The pinnatisect leaves and elevated disk are the most conspicuous features in this species. The ray-florets are bright yellow, or orange-red and yellow, and in one variety they are fewer in number and broader than those represented in the figure. A native of Texas, growing from 2 to 3 feet high, and flowering in August.
3. R. fulgida, syn. R. chrysomela. - A distinct species about 2 feet high with leafy peduncles and yellow flowers about 2 inches in diameter with a purplish brown centre. Ray-florets numerous, emarginate. A North American species flowering in July and August.
R. elegans of dwarfer habit, and R. grandifiora with larger flowers, are near the last. The latter is rather tender.