American Hog Peanut
Amphicarpaea bracteata is classified in the Pea family (legumes), which is not surprising given its common name. Like other plants in the Pea family, American hog peanut is a vining plant that climbs its way upward with the support of adjacent plants; this feat is accomplished without tendrils. Instead the branching vine coils around the sturdy stems of neighboring plants. Preferring moist habitats, it grows in the shade or part-shade of moist woods and thickets, flowering July through September. I found these flowers while hiking along the road among the understory foliage of our northern mesic hardwood forest of ironwood, maples, basswood and red oak trees. The leaves are compound growing in 3s, with the middle leaf being larger than the two below it on the sides.
Interestingly — and somewhat unusual — hog peanut produces two kinds of flowers; and even more interestingly, two kinds of fruit to correspond. More about its name, then, Amphi, from the Greek means ‘of both kinds’ and karpós, Ancient Greek translates as ‘fruit’. The name ‘hog peanut’ comes from self-fertile flowers that grow along the ground surface (and sometimes subterranean) in the form of a tuber. This type of self-fertile flower is termed ‘cleistogamous’ and does not have petals. The tubers from these self-fertile flowers are edible to humans (raw or boiled?) as well as many other creatures who enjoy them as part of their diet, list of animals. These creatures, unlike humans, consume both kinds of the fruit.
Hog peanut’s ‘regular’ type flowers growing above ground among the foliage, with petals and all the other male and female flower parts with the usual requirement for cross pollination. Fruits are also formed from these flowers taking the shape of pea pods with seeds inside. July through September, hog peanut can be found in the shade to part shade and moist soils of the woods, winding its way upwards using tendrils to grasp onto whatever neighboring plants may be growing adjacent to it. Not surprisingly (given its name), American hog peanut is classified in the Pea family, and is a soil nitrogen-fixer like other legumes. The bean of this fruit if edible.
https://www.illinoiswildflowers.info/savanna/plants/hog_peanut.html
https://www.friendsofthewildflowergarden.org/pages/plants/hogpeanut.html