impatiens capensis
January 24, 2021Impatiens capensis (also known as orange jewelweed, spotted jewelweed, orange balsam, and [spotted] touch-me-not) is an annual plant native to eastern North America. It is considered invasive to the Pacific Northwest, common in bottomland soils, ditches, and along creeks, grows 3-5 feet tall and blooms from late spring to early fall, and often branches extensively.
The seed pods have five valves which coil back rapidly to eject the seeds in a process called explosive dehiscence or ballistochory. This reaction is where the name ‘touch-me-not’ comes from. In mature seed pods, dehiscence can easily be triggered with a light touch. The juice of the leaves and stems has been used as an herbal remedy for skin rashes, including poison ivy.
There is some uncertainty in etymology, with possible sources being the leaves which appear to be silver or ‘jeweled’ when held underwater, and the color and shape of the bright robin’s egg-blue’ kernels of the green projectile seeds. The species name capensis, meaning “of the cape,” is actually a misnomer, as Nicolaas Meerburgh erroneously believed that it was native to the Cape of Good Hope, in southern Africa.
references:
1: “BSBI List 2007”. Botanical Society of Britain and Ireland.
2: “Impatiens Capensis Meerb.” Impatiens Capensis (Jewelweed, Spotted Touch-Me-Not): Go Botany, © 2021 Native Plant Trust.
3: Hayashi, Marika; Feilich, Kara; Ellerby, David (May 2009). “The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis)”. Journal of Experimental Botany. 60 (7): 2045–2046.
4: Smith, Huron H. (1933). “Ethnobotany of the Forest Potawatomi Indians”. Bulletin of the Public Museum of the City of Milwaukee. 7: 42.
5: Strausbaugh, P.D.; Core, E. L. (1964). Flora of West Virginia (2nd ed.). Seneca Books. p. 622.