This week, I’m featuring Wild Bean (Apios americana) as one of our local wildflowers that begins to bloom at this time.
PLEASE NOTE: Culturally Significant Plant = Ethnobotanic Uses: Wild Bean (AKA American Groundnut, American Potato Bean, or Hopniss) was a source of food among the Omaha, Dakota, Santee Sioux, Cheyenne, Osage, Pawnee, and Hidatsa. Read more.
Description:
This native perennial twining vine can grow up to 7 to 10 feet in length and has no tendrils. Although the plant does well in open areas by trailing, the vines readily climb up vertical supports such as woody or sturdy erect herbaceous plants.
At intervals along these stems, there occurs alternate compound leaves that are odd-pinnate with 3-7 leaflets (usually 5 leaflets and rarely 3 leaflets) and the terminal leaflet is larger and on a longer stalk. The leaflets are 1½–3½” long and ¾–2¼” across; they are lancelike, oblong, ovate, or broadly ovate in shape with toothless margins. The upper leaflet surface is medium to dark green and hairless, while the lower leaflet surface is either light green or whitened green and hairless to minutely hairy. The stem (petioles, which are less than ¼” long) and the central stalks (rachises) of the compound leaves are light green, narrowly furrowed above, convex below, and hairless to minutely pubescent. The foliage of this vine contains a milky sap.
The flowers are pink on the outside, and maroon to a rich brown on the inside. The top of each flower has a curved horn-like structure that functions as a hood over the other floral parts. Flowers are arranged in dense, conical clusters (racemes) 2 to 6” in length arising from the leaf axil; each is pea-like, yet unique and distinctive. The basal stalks of these racemes are up to 3″ long, light green, and hairless to minutely hairy. The central stalk of the raceme (floral rachis) is light green, hairless to finely short-hairy, and bumpy from small tubercles; these tubercles are extra-floral nectaries that secret droplets of nectar shortly after the flowers and their pedicels become detached from the floral rachis.
Photo Credit: (c) G. D. Bebeau, https://www.friendsofthewildflowergarden.org/pages/plants/groundnut.html
Afterwards, fertile flowers are replaced by slender cylindrical seedpods about 2 to 4″ long and 1/5” across that are light green to yellowish green. These seedpods are often slightly curved (up or down) and slightly compressed along their sides. However, some vines are sterile and they don’t produce seedpods after the flowers bloom.
https://www.ecolandscaping.org/09/developing-healthy-landscapes/ecological-landscaping-101/edible-and-landscape-worthy-native-plants-of-new-england/
The seedpods each contain several seeds; eventually they divide into 2 parts, ejecting their seeds. The smooth seeds are ~3/16” long, green, and appear inflated when fresh and then become dark brown and more chunky in appearance when dry.
Culinary and Medicinal Uses:
Both the seeds and tubers are edible to humans, but the tubers were considered an excellent source of food by both early pioneers and American Indians. The tubers saved the Massachusetts Bay Pilgrims from starvation during those first difficult winters.
Wild Bean produces small tubers that are arranged along individual rhizomes like a knotted rope; however, it takes two to three years for them to reach harvesting size. The tubers are highly palatable with culinary characteristics of a potato, although the flavor can be somewhat nuttier than a potato and the texture can be finer. As with many other legumes, this plant can fix atmospheric nitrogen in the soil through a symbiosis with rhizobial bacteria. Therefore, compared to other commonly eaten tubers and root vegetables, the tubers of Wild Bean are unusually high in protein, containing roughly three times the protein content of a potato and 17% protein by mass.
It is not recommend to eat the raw tubers due to the presence of protease inhibitors that interfere with protein hydrolysis and act as an anti-nutrient. Cooking the tubers destroys these compounds and eliminates this problem.
American Indians would prepare the tubers in a variety of ways, such as frying them in animal fat or drying them into flour. The Menomini make a preserve of the tubers by boiling them in maple syrup. The tuber can also be dried and ground into a powder that is then used as a thickening in soups or can be added to cereal flours when making bread.
While there are few known medicinal uses of this plant, the tubers were boiled and made into a plaster and used in folk remedies for the skin wound condition known as “Proud Flesh” in colonial New England.
Wildlife Value:
The flowers are visited primarily by bees for nectar and, to a lesser extent, pollen. This includes bumblebees, Halictid bees, honeybees, and leafcutting bees. Leaf-cutting bees are considered the most important cross-pollinators of these flowers. Ground Yellow Jackets (Vespula spp.) have also been reported to visit the flowers, but to a lesser extent.
Wild Bean is the larval host plant for the caterpillars of Silver-spotted Skipper (Epargyreus clarus) and Southern Cloudywing (Thorybes bathyllus).
White-tailed Deer (Odocoileus virginianus) browse the foliage of this vine.
Where Found Locally:
- 100 Acre Wood
- Ann Lee Pond Nature and Historic Preserve
- Ballston Creek Preserve
- Balsam Way Natural Area
- Community Connector Trail
- Dwaas Kill Nature Preserve
- Hayes Nature Park
- Historic Champlain Canalway Trail
- Old Iron Springs Fitness Trail
- Peter Desrochers Memorial Country Knolls Trails
- Shenantaha Creek Park
- Stillwater Multi-Use Trail
- Summer Hill Natural Area
- Swatling Falls Nature Trails
- Town Park nature trails
- Veterans Memorial Park
- West Sky Natural Area
- Zim Smith Trail
Curious By Nature 
