Wake Audubon Blog

The Little Brown Jug

i Apr 7th No Comments by

One of my favorite spring wildflowers is the Little Brown Jug, or Arrow-leaved Heartleaf (Hexastylis arifolia). It’s also one of the most common wildflowers in the Raleigh area. You’ll see them growing in deciduous and mixed woodlands over much of Wake County and the surrounding area. What you generally see are the leaves, which are triangular in shape and somewhat fleshy, nestled in the leaf litter on the forest floor. For most of the year, the leaves have distinctive pale patches between the major veins. This time of year, when the new leaves are unfurling, you’ll see the pale blotches only on last year’s leaves. It takes a while before the new leaves develop their mature coloring. The leaf blades are two or three inches long, with a leafstalk that’s usually about six or eight inches long. The leafstalks lop down on the ground.
What you don’t usually see are the flowers, but they’re blooming this month. If you bend down, brush the fallen tree leaves away, and follow the leafstalks to the base of the Little Brown Jug plant, you’ll see the jugs, the flowers that give the plant its name: brown, vase-shaped, and about an inch long, with three pointed lobes at the mouth of each jug. Within those jugs, some of the most interesting facts about the plant’s life reside. The whole plant has a gingery odor, and this odor attracts fungus gnats, which crawl inside the flowers and pollinate them. Although the plants are self-fertile, they still need the gnats to transport the pollen from the anthers to the stigmas. After about a month and a half, seeds develop at the base of the jug. Each jug produces, on average, about twenty seeds, and each seed is about eight tenths of a millimeter long, hardly longer than a poppy seed. However, the plant now needs help from a different insect: ants. Like many forest wildflowers, the Little Brown Jug uses ants to disperse its seeds, and to entice the ants it produces a small, fat-rich appendage on each seed. The ants carry the seeds off, eat the appendages, and leave the rest of the seed near their nest.

The first year after the seeds sprout, only the cotyledons appear. During the second year a single leaf grows. It may take seven or eight years before a plant is ready to bloom. The plants are fully perennial, though, and can live for up to twenty years. Watch for them the next time you stroll through a forest here in the Triangle, and bend down to see if you can find the jugs.

Erik Thomas, Wake Audubon Board Member