Plants of the Eloise Butler Wildflower Garden

Spotted touch-me-not is an erect native annual. Stems are succulent, somewhat translucent, 2 to 5 feet high, easily broken, branching occasionally.

Leaves are thin, egg shape with coarse broad teeth and slender long stalks. In dry conditions leaves can become thicker. Submerged in water, they take on a silvery sheen.

The inflorescence is a long-stalked cluster of up to 3 flowers that rises from the leaf axils.

Flowers: Spotted touch-me-not has two types of flowers - chasmogamous, which open for fertilization and cleistogamous, which do not open and self-fertilize. The chasmogamous are 1 inch long flowers hanging on a long drooping freely moving stalk (pedicel) and the flowers have a curved nectar spur at the back end. The amount of curve is quite variable but can be as much as 270 degrees. The flower stalk has a small linear bract in mid-stalk. The flower stalk is attached just above the mouth of the corolla where one petal and three sepals come together. Flowers have 5 petals that seem fused together in places. These form the upper lip projecting out like a hood, two laterals and two larger lower lips which flare outward. There are 3 sepals, with the larger forming the cone of the back of the flower and the nectar spur; the other two are a much lighter color and seen on the top of the corolla behind the upper lip. Five stamens with yellowish anthers are united around the single pistil and the assemblage is tucked up under the upper lip. The petals are spotted with deeper colored reddish spots as is the large sepal occassionally.

These flowers are sexually dichogamous, that is, with the male and female parts maturing at different times, thus avoiding something nature does not like - self pollination. The male parts are ready first and the anthers are ready for pollen release for only a twenty-four hour period, then the anthers are dropped and the female stigma is exposed. The receptive phase then follows when the stigma can receive pollen from a flower that still has pollen for release but that phase is very short - average of four hours according to experiments that have run.

The cleistogamous flowers are found singly in the lower leaf axils and require only three weeks to mature. These are usually produced later in the season. These are only 1 to 2 mm in diameter. These flowers produce seed when, through stress or other climatic conditions, the regular open flowers are few or cannot be pollinated. Also, since the type of pollinator required for the open flowers, due to its deep nectar sac, is quite limited, and also since the plant is an annual, cleistogamous seed production insures that the species will re-seed.

The fruit is a pod that when mature will explode and expel the seed some distance - hence the common name of "touch-me-not" (see Thoreau's notes at bottom of page). Seeds are longer than wide, brown with lighter ridges and usually number 3 to 5 per pod. The cleistogamous flowers also form seed pods but contain fewer seeds. Hummingbirds and large bees are the prime pollinators. By a hummingbird inserting its long tongue into the curved nectar spur, the spur is pushed away with each lick of the tongue and then the spring-like action of the pedicel brings the flower back toward the bird causing the anthers or the stigma to contact the back portion of the birds bill, thus transferring pollen. [see Mobility of Impatiens capensis flowers: Effect on pollen deposition and hummingbird foraging by Hurlbert, Hosoi, Temeles and Ewald, Spring 1996 published in Oecologia.] For details on the mechanism that releases the seeds explosively, see this article (pdf). Another article that covers in detail the research on the open and closed flower types in this species is Jewelweed's Sexual Skills, by Donald M. Walker, University of Wisconsin, in Natural History, Vol. 91 #5. and also papers in Evolution, Vols. 34, 38, 41.

Habitat: Touch-me-nots are plants of moist places with full to partial sunlight. They are true annuals. Because of this their abundance varies from year to year - and they are found only in moist areas of the Garden during drier years otherwise they adapt to drier soils when there is sufficient rainfall. They are somewhat drought tolerant with plant size and flower production affected.

Names: The genus name impatiens is Latin for "impatient" referring to the characteristic of the seed to explode from the dry seed head. The species capensis, means 'of the Cape of Good Hope, South Africa,' but this was a mistake by the plant author who was under the impression the species was native there. You will see this plant listed with an older, now replaced, species name -I. biflora. The alternate old common name “Wild Balsam” is derived from the Latin family name for the species, BALSAMINACEAE. The author name for the plant classification - ‘Meerb.’ is for Nicolaas Meerburgh (1734-1814) Dutch botanist who was director of the botanical garden in Leiden and most known for his 5 volumes of Portraits of Rare Plants (Afbeeldingen van zeldzame gewassen.)

Comparisons: Spotted Touch-me-not has orange flowers with red-brown spots. The spur on the back bends underneath and forward and upward and is usually parallel to the flower but not at a right angle downward like the Pale Touch-me-not (Impatiens pallida), which is also slightly larger, however, there are variations depending on the maturity of the flower.