Mystery plant: Keep your dogs away from this one
Saturday, January 13, 2018
Down, down, dogs! — Shakespeare, Henry IV, part 2; II, 4.
I know that there are plenty of dog lovers (like me) out there reading this essay. We have two rescue dogs at our house, both locally born and “bred.” I don’t know what I’d do without them at this point, and of course we provide them with a yard to run around in, access to a dog park, comfy bedding, tasty dinners, the dog-salon and a complete medical/dental package. No wonder that we are careful with what is allowed, plant-wise, to come up in the backyard, as both of my girls, Rosie and Hannah, have good appetites, which are, shall we say, rather comprehensive. This is a plant we won’t allow them to fool around with.
In fact, its Greek name (the genus) means “Scram, dog!” For ages this plant has been known to have relatively serious toxic properties, and a good many critters have been sickened after consuming parts of it. The toxic part of the plant resides in its juice, which, while the plants are alive and growing, will be somewhat white, oozing from wounds from fresh tissue. We botanists call this juice “latex.”
The plants themselves are handsome. This native species is a member of the milkweed family, and it can be found on upland sites nearly throughout the United States. It’s a strong-stemmed herb, growing straight up without branching except at the top, getting up to 3 feet tall. The leaves are broad and somewhat egg-shaped, bright green. Flowers are small and white. Following blooming, fruits will be set. In this case, each flower will produce a pair of “twinned” fruits; “follicles,” actually, which open up along a single slit down its length. The ripe, dry fruits can be seen in the autumn and winter, releasing their many seeds. Each seed is equipped with a silky parachute allowing wind distribution, much like what we see with seeds of … milkweeds.
The latex produced in the stems and leaves, due its complicated chemical nature, is not only a bit toxic, but has a considerable history of medicinal use. The historic use of this plant in medicine, at least during the Revolutionary and Civil wars, is well documented. South Carolina’s own Francis Peyre Porcher, in his 1869 publication “Resources of the Southern Fields and Forests,” refers to the use of the plant for treating dropsy (edema), substituting for quinine, as a great emetic (yuck), diuretic, “and as an agent for removing ascarides [worms]” … (yuck again).
Besides this plant’s positive reputation for healing powers, it is probably better known historically as a source of excellent fibers, rivaling those obtained from true “hemp,” Cannabis sativa. Native Americans commonly fashioned various sorts of “cordage” from fibers obtained from the stems. Do you think anybody has ever tried using these fibers to make dog leashes?
(More on medicinal plant use and Southeastern wildflowers will be found in “A Guide to the Wildflowers of South Carolina”, by Richard Porcher [yes…a relative of the 1869 author!] and Doug Rayner, USC Press, 2001.)
[Answer: “Dogbane,” Apocynum cannabinum]
John Nelson is the curator of the A.C. Moore Herbarium at the University of South Carolina’s Department of Biological Sciences in Columbia, S.C. As a public service, the Herbarium offers free plant identifications. For more information, call 803-777-8196, visit www.herbarium.org or email firstname.lastname@example.org.