Holy grail of plants found in one State Natural Area

A Wisconsin DNR conservation biologist has found the “holy grail” of a rare plant in Wisconsin: a green violet, long thought gone from the state, but growing by the hundreds in a State Natural Area (SNA) in west central Wisconsin.

The species (Hybanthus concolor) was last documented in Wisconsin, in 1958, when it was collected from a site in Grant County. That site was severely impacted by grazing and the species was thought to no longer grow in the state.

“It was pretty exciting,” said the discovering DNR con- servation biologist Ryan O’Connor. “It really drives home several things, including that there are still important things to discover on SNAs, and that our SNAs are vital to the conservation of plants and animals, some of which are found nowhere else in the state.”

Green violets are native to the eastern United States, while Wisconsin is at the very northern edge of the green violet range. Across its range, green violet is limited to rich mesic forests on limestone soil. Many of these sites have been lost to logging, grazing, and invasion by weeds like garlic mustard and honeysuckle.

Most violets have white, yellow or purple petals, and green sepals, but green violet has much less showy flowers. Like other violets, green violet has a gelatinous substance, called an elaiosome, attached to its seeds. The elaiosome is rich in fats and proteins, which attract ants.

The ants bring the elaiosomes back to their nests to eat and as they move them around, distribute the violet seeds.

This isn’t the first rare plant finding within Wisconsin’s SNAs – 75 percent of wildlife species listed in Wisconsin as threatened or endangered, and 90 percent of state-listed plants, are supported on SNAs.

These sites, owned by the DNR and more than 50 partners, represent Wisconsin’s best native forests, wetlands, prairies, and geological and archaeological sites. Their primary purpose is to maintain this natural heritage for future generations.

O’Connor’s discovery also underscores the importance of having experts conduct “biotic inventory surveys” to document the different rare species on state-owned lands and assess how the natural community they are part of is faring.

The state legislature created the SNA program to conserve examples of these communities, 70 years ago.