Plants of the Eloise Butler Wildflower Garden

Turtleheads have flowers where the upper lip arches over the lower lip giving the resemblance to a turtle's head. White Turtlehead is a native erect perennial forb growing on smooth 4-sided stems, usually about 2 to 4 feet high (some to 7.5 feet) and usually unbranched below the inflorescence, but branched within. Stems are usually multiple from the root.

The leaves are long, 6x as long as wide, 9 inches at the longest, lance shaped, sharp toothed, opposite, and hairless. They have pointed tips, are narrowed at the base - the lower stem leaves are toothed, taper to a short stalk, while the upper leaves can be clasping and have margins without teeth. The upper surface is smooth while the lower surface can vary from smooth to finely hairy. Each pair is usually rotated 90 degrees from the adjacent pair on the stem. 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 page bottom)

The inflorescence is a dense short spike at the top of the stem and on axillary stems from the upper leaf axils. Flowers open from the bottom to the top of the spike.

The white flowers (can have a pink tinge) have two almost closed lips. The upper lip has two shallow lobes. The lower lip has three lobes with the center one bearded inside. The flower tube is 1 to 1-1/2 inches long. Inside 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 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, has a green tip and usually lies at the base of the tube. The green calyx has 5 ovate-oblong segments with rounded lobes. At the base of the calyx are several green bracts with smooth surfaces.

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 projection. 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. (Reference below).

Seed: Fertile flowers produce an ovoid seed capsule, twice as long as the calyx, containing flatten seeds that have wide wings for wind dispersal. Turtlehead seeds are best planted outdoors in the fall as the seeds need at least 120 days of cold stratification for germination.

Habitat: Turtlehead grows from a rhizomatous root system which allows it to colonize. It requires fertile moist soil and full sun for stout plants. These plants appear in a few places in the bog area of Eloise Butler but are greatly outnumbered by the Red Turtlehead.

Names: The genus name Chelone from the Greek chelon, 'tortoise' and the species name glabra means 'smooth' - no hair on the calyx, stem and, most of time, on the leaves 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.

Comparison: Red Turtlehead, Chelone obliqua, has a similar flower, but pink in color and the leaves are distinctly different, being more ovate, a longer stalk and a different vein pattern.