Green-headed Coneflower is a native erect perennial forb growing on stems that can reach 7+ feet in height, are smooth and branch near the top into multiple flower heads. The text here treats var. laciniata.
The leaves vary in shape and size with the lower leaves being palmately divided into 5 to 9 lobes with serrate irregular edges. Mid-stem leaves will have fewer lobes than basal leaves and then graduating up the stem to 3 lobed or un-lobed and then to bracts within the floral array. Leaf petioles have a shallow groove. Leaf surfaces are usually smooth or with only sparse hair.
The floral array consists of branched clusters of several to many heads, each head on a long stalk and the cluster itself on a long stalk held above the leaves.
The flower heads are composite with both ray and disc florets. Ray florets can make the head 2 1/2 to 4 inches wide. There are 8 to 12 yellow drooping rays which are sterile. These are smooth on the upper surface, slightly hairy on the underside. The fertile florets of the central disc number 150 to 300+, have a tubular yellow to yellowish-green corolla (turning dark brown at maturity), with five yellow lobes at the tip and 5 stamens with purple anthers. The style is yellow, split into two tips, and is tightly surrounded by the stamens. Style and stamens are exserted from the corolla throat when receptive. The corolla lobes do not spread outward when in flower. Around the outside of the flower head are several series of phyllaries (bracts) that number 8 to 15, are of unequal length, pointed, and some stick out between the yellow rays. These can have some fine hair, particularly on the margins. The central disc is domed, slightly flattened at first, then more hemispherical when all the florets have opened.
Seed: Flowers mature to a dry seed (a cypsela) 4.2 to 6 mm long, without fluffy pappus (but with short bristles), conical in shape, ribbed, with crown-like projections at the larger end. Seed dispersion is by wind shaking the stem. Seeds require 30 days of cold stratification for germination.
Varieties: Five are recognized: One has an ovoid shaped receptacle - var. ampla. Four have a globose to hemispheric receptacle - var. heterophylla where the leaves are not lobed; var. digitata where the lower leaves have 3 to 5 lobes but are not pinnatifid (fern like); var. bipinnata where the lower stem leaves are 2-pinnatifid and cypselae are 3.5 to 4 mm long; and finally var. laciniata where the lower stem leaves are pinnatifid only and the cypselae are 4.2 to 6 mm long. This is the variety native to Minnesota.
Habitat: Green-headed Coneflower grows best in full sun and somewhat moist soil. It also grows well in partial shade in moist soils. It has a rhizomatous and fibrous root system, but does not spread agressively.
Names: The genus Rudbeckia, is named after the Swedish father and son, - O. J. and O. O. Rudbeck, who were professors of botany and predecessors of Linnaeus. The species name laciniata, is from the Latin meaning 'slashed' or 'torn' which is the look of the leaves. The author name for the plant classification, 'L.', refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Comparisons: The flower form is similar to the Gray-headed Coneflower, Ratibida pinnata, but there the leaf is composed of leaflets, not just palmately divided and the floral array has only one or several heads, not a branched cluster. A much shorter plant is the Long-headed Coneflower, Ratibida columnifera, (also called Prairie Coneflower) which, as the name implies, has a much taller disc cone. See notes below on the commercial "Goldenglow".
Above: 1st photo - The floral array consists of branched clusters of several to many heads. 2nd photo - Ray florets are long and drooping.
Above and below: Green-headed Coneflower blooms of mid-August. In the photo below note the flowers of the central disc that have a yellow corolla, five lobes and 5 stamens with dark anthers that surround the single style. The florets turn brown after fertilization.
Below: 1st photo - Detail of the central disc of the fertile disc flowers. 2nd photo The lance-shaped phyllaries of the flower head are of unequal length, some reflexed, and are visible between the yellow ray flowers.
Below: 1st photo - Lower leaf (note the Groundnut flower clinging to a stem at top of photo) 2nd photo - Upper leaf
Below: 1st photo - A full size lower leaf. 2nd photo - The appearance of a flower head as the first rays begin to appear.
Below: The basal rosette of leaves in early Spring.
Below: The cypselae (seeds) are conical with short bristles and crown-like projections on the wide end.
Below: An example of branching in the inflorescence and multiple flower heads - Upland Garden at Eloise Butler August 27, 1999.
Notes: Green-headed Coneflower is indigenous to the Garden area; Eloise Butler cataloged it on Sept. 6, 1907. Martha Crone also listed the plant on her 1951 Garden Census. Susan Wilkins added plants in 2011. Green-headed Coneflower is native to most counties in Minnesota except a few in the SW and in the far North Central. Absent in Cook County. It is widely distributed in North America - found in most of the states except CA, NV and OR, and found in most lower Canadian Provinces except Alberta and Saskatchewan. There are five listed varieties of the plant with the variety laciniata considered by the University of Minnesota to be the species native to Minnesota. The distinguishing characteristic of this variety is that the lower stem leaves are pinnatifid, the mid-stem leaves have 5 to 9 lobes and there are differences in the size of the seed and the bristles.
Four species of Rudbeckia are considered native to Minnesota: R. laciniata var. laciniata, Green-headed (or Tall) Coneflower; R. hirta, Black-eyed Susan; R. triloba, Three-leaved (or Thin-leaved) Coneflower; and R. subtomentosa, Sweet Coneflower (Sweet Black-eyed Susan), although the latter is considered either an introduction or an extension of its normal range from Iowa and southern Wisconsin, as there is only one known population in the wild, in Mower County. The nursery trade has produced cultivars of Green-headed Coneflower, known commercially as Golden-glow, which is widely planted and occasionally escapes from cultivation. The flower head of commercial Golden-glow has numerous ray florets and a much reduced center disc.
Eloise Butler wrote: "Veritable fields of cloth of gold are now gleaming with sunflowers, coneflowers and golden rods, not for kings alone, but for all the people. In this display of gold the tall coneflower, Rudbeckia laciniata, takes the lead - a brother of Black-eyed Susan, with eyes of golden brown, fringed with longer, drooping lashes of paler yellow" text from writing of Aug. 13, 1911.
Lore: In her study of the Minnesota Chippewa, Frances Densmore (Ref. #5) reports the use of this plant in their native medicine. The root and with equal parts of the root of Caulophyllum thalictroides (Blue Cohosh) were steeped in water and then the fluid was drank to cure indigestion. A treatment for burns was a poultice made from the flowers of Giant Hyssop, Canada Goldenrod and the flowers of R. laciniata.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"