Turtleheads have flowers where the upper lip arches over the lower lip giving the resemblance to a turtle's head. The Red Turtlehead is a native perennial forb with slender green smooth stems, slightly 4-angled, that are usually about 2 to 3 feet high and usually branched, although 6 feet in height is known.
Leaves are opposite, lanceolate to oblong, toothed, stalked with a narrowing leaf base and a tip tapering to a point. The upper surface is smooth, a medium to dark green, the underside paler sometimes with very fine hair. Leaf margins are toothed to double-toothed. Depending on the variety, blades vary from 2 to 7-5/8 inches long. The leaves of Chelone contain two chemicals which deter a number of plant browsers from eating them - the chemicals, metabolites, are iridoid glycosides aucubin and catalpol. (see reference article at bottom of page.)
The inflorescence is a short dense terminal spike of of stalkless erect flowers.
Flowers have deep pink tubular corolla that has two upper lobes and 3 lower lobes, with the center lobe bearded with yellow hairs and slightly elevated. Inside the corolla tube are 5 stamens and a style. The short style and four of the stamens that are true are appressed to the upper part of the corolla tube, the stamens are in pairs, almost joined, until forced apart by large bees. The pollen sacs of these stamens are covered with dense hairs. The fifth sometimes degenerated stamen (a staminode) is short, white, and usually lies at the base of the tube. The length of the staminode is a determining factor in the varieties. The outer calyx has 5 green lobes with ovate rounded tips. Also behind the calyx are short green bracts.
The Chelone genus is protandrous, that is the male segments of the flower mature before the female parts. When the pollen sacs mature, attracting large bees, nectar production is low, but then the flower enters the female phase and the style, formerly recessed in the upper lobe, elongates and recurves downward, placing the stigma near the entrance to the corolla and in front of the anthers, thus picking up pollen from late pollen gathering bees as they leave the flower. These late bees are also now attracted by an increase in nectar production. Thus Chelone even though it is protandros, can set seed from its own pollen (autogamous) but requires a later second visit by a pollen gathering bee to do so.
Seed: Fertile flowers produce an ovoid seed capsule, twice as long as the calyx, containing dry seeds that are shaken loose with the wind or remain in the capsule until it falls off in the winter or spring. Turtlehead seeds are best planted outdoors in the fall as the seeds need at least 120 days of cold stratification for germination. They are very small and encased in winged membrane.
Varieties: Three are recognized: var. speciosa where the calyx lobes are dense with fine hair and the staminode is 4 to 8 mm long; two varieties where the staminode is 8 to 12 mm long - var. obliqua with mid-stem leaf bades 2 - 3-1/8 inches long, back corolla lobes more than 15 mm long; and var. erwiniae with mid-stem leaf blades at least 3-1/8 and up to 7-5/8 inches long, with back ccorolla lobes no more than 15 mm. Var. speciosa is considered the Minnesota native variety.
Habitat: Red Turtlehead grows from a rhizomatous root systems which allows it to colonize. It requires fertile mostly wet soil and full sun for stout plants.
Names: The genus name, Chelone, is from the Greek chelon, for tortoise which then leads to the common name. The species obliqua means 'oblique' or 'lopsided' and refers the shape of the seed. The author name for the plant classification - 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. The newest reclassification puts this plant into the Plantaginaceae (Plantain) family and removes it from the Figwort (Scrophulariaceae) family.
Comparisons: Red Turtlehead appears in a few places in the wetland area of Eloise Butler and in a very large grouping near station 24 on the boardwalk. The reds greatly outnumber the White Turtlehead (Chelone glabra L.) which is also in the wetland area. White Turtlehead has a more open panicle, shorter leaf stalks and leaves that are more linear. See notes below on the history of Red Turtlehead in the Garden.
Above: Blooms of late August into September. The green lobes of the calyx are visible in the 2nd photo.
Below: 1st photo - Flower bud emerging. 2nd photo - Leaf type.
Below: Seeds capsules will remain through the winter for visual interest. Seeds are encased in a winged membrane.
Below: An example of Pink Turtlehead resembling C. lyoni.
Below: Red Turtlehead in Eloise Butler - 2018
Notes: Eloise Butler first brought in plants on August 14, 1926 from the vicinity of Waterville MN, near the southern boundary of Rice County - 1 clump. These had been naturalized in Mr. Rohl’s garden, Gramercy Ave. Then they were stolen and Policeman Rohl replaced the clump with others from his garden on May 23, 1931. There was speculation in later years by Gardener Cary George that these plants were Pink Turtlehead, Chelone lyoni Pursh, a plant native to the Southeastern United States and in Minnesota is a garden escapee, but Martha Crone's 1951 inventory of plants in the Garden at that time listed it as C. obliqua.
The Red Turtlehead (Chelone obliqua) is considered native to Minnesota but distribution in the state is not well documented. The Checklist of the Vascular Plants of Minnesota (Ref. #28C) still lists the plant but the 2019 DNR census report does not list it. It (Red Turtlehead) is on the threatened or endangered list is several states, Michigan, being the closest to us in Minnesota. C. obliqua distribution in the U.S. is limited to a group of eight states in the Mississippi and Ohio River valleys - AR, IA, IL, IN, KY, MI, MN and MO and as stated, the distribution in Minnesota is questionable. Martha Crone noted planting Red Turtlehead in 1946, '47, '48, and '57. Perhaps both species were involved with these plantings. Some of the plants in the Garden are reported by the Garden staff to be C. obliqua while other individuals have characteristics of both C. obliqua and C. lyoni on a single plant, undoubtedly due to hybridizing.
Technical Reference: A paper titled POLLINATION ECOLOGY AND FLORAL VISITOR SPECTRUM OF TURTLEHEAD by Richardson and Irwin was published in 2015 in the Journal of Pollination Ecology. It reports of research of how pollination is accomplished in the Chelone genus with some specific research on Chelone grabra. [PDF copy]
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"