Gray-headed Coneflower is a native erect perennial forb with slightly ridged stems growing 3 to 4 feet high. Stems usually have short rough hair.
Leaves: The larger lower leaves are pinnately divided into 3 to 7 skeletal stalked leaflets, with the larger leaflets sometimes having lobes. Leaves decrease in size toward the top of the stem with the leaflets becoming more lance-shaped and the very upper leaves are usually stalkless. Leaves have a rough surface texture from short stiff hairs.
The floral array consists of one to several flower heads rising well above the leaves on long stalks from the tops of the stems. The heads do not form a cluster.
The flowers are composite with both ray and disc florets. The ray florets number 6 to 15 with yellow rays of 1 to 2-1/2 inches long, that are narrow and drooping. These are sterile. The central disc is longer (taller) than it is wide, composed of 100 to 200+ disc florets whose corollas are initially greenish-yellow to gray in color with the outer parts changing to dark brownish-purple as the flowers open. The disc flowers are fertile, with a 5-lobed corolla and 5 stamens. The filaments of the stamens appress tight against the single style. The outside of the flower-head has 10 to 15 green phyllaries (floral bracts) that are in two series, linear in shape with the outer slightly longer than the inner.
Seed: The fertile flowers produce a dry cypsela, 1.2–3 × 1.2–2 mm in size, without pappus but with 1 or 2 tooth-like projections. These are shaken loose from the cone by the wind and are light enough to be carried a short distance. Seeds require 30 days of cold stratification for germination.
Habitat: Gray-headed Coneflower grows from a rhizomatous root system and tends to form clumps by the spreading rhizomes. It requires sunny open areas with mesic to dry conditions, adapting to many soil types.
Names: The genus Ratibida is an older, now obscure, name that has been re-applied to this species which was formerly in the genus Lepachys. The species pinnata, means 'feather-like' referring to the leaves which have fine segments arranged along a common stem - referring here to the separate leaflets of the major leaves. The author names for the plant classification starts with ‘Vent.’ who is Étienne Pierre Ventenat (1757-1808), French botanist who published several works about plants in French gardens including the rare plants of Malmaison. French gardens grew many species imported from the New World. His work was updated by ‘Barnhart’ who is John Hendley Barnhart (1871-1949), American botanist and author who was Bibliographer of the New York Botanical Garden.
Comparisons: Gray-headed Coneflower resembles Green-headed coneflower (Rudbeckia laciniata) except that there the height of the disc is lower and the large lower leaves are palmate instead of pinnately divided. 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.
Above: 1st photo - Flowers are on a long stalk will above the leaves. 2nd photo - Disc florets open from the bottom of the cone upward. 3rd photo - The flower head has 2 series of phyllaries, 10 to 15 in number.
Below: 1st photo - An upper leaf. 2nd photo - A large long-stalked lower leaf with multiple leaflets, some of which have lobes. Surfaces of the leaflets and stalk are rough to the touch. The species name, pinnata, is due to the shape of the large lower leaf.
Below: Disc flowers of the cone number 100 to 200+. As they mature the corolla elongates and becomes purplish-brown. There are 5 stamens with yellow anthers. The yellow ray flowers beneath are sterile.
Below: The rhizomes of the root.
Below: Flowers of late summer. 2nd photo has plant rising among leaves of False Indigo.
Notes: Gray-headed Coneflower was first introduced to the Garden by Eloise Butler on July 12, 1910 with plants she obtained from the grounds of the Agricultural College in St. Paul. She listed it under its older botanical name Lepachys pinnata. Martha Crone planted 5 of them in July 1945 and more in 1956. It was listed on her 1951 inventory of plants in the Garden at that time. Cary George reported planting it in 1995.
Gray-headed Coneflower is native to Minnesota across the Southern third of the state and to a few counties in North Central. In North America is has much less range than the Green-headed Coneflower (Rudbeckia laciniata), being found in the eastern half of the country only, excluding New England. In Canada it is known only from Ontario.
Only two members of the genus Ratibida are found in Minnesota. This one, R. pinnata, and the Long-headed Coneflower, R. columnifera.
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"