Missouri bladderpod is a small, yellow-flowered member of the mustard family that is found only in southwest Missouri and northwestern Arkansas. It gets its name from the spherical fruits or “bladders” that contain seeds.
Missouri bladderpod is a nonwoody, annual plant that produces numerous slender stems from its base. Both the leaves and the stems have a dense covering of fine hairs, which gives the plant a silvery-gray appearance. (With magnification, you will see the hairs are star-shaped.)
The leaves are less than an inch long and taper toward the stems. The basal and stem leaves have different shapes: the basal leaves are rather circular or spatula-shaped, with leaf stems; the stem leaves are increasingly narrower and smaller, the highest stemless.
Blooms April–May.
The flowers are typical mustard flowers, with four petals and four sepals. The petals are yellow.
The fruits are spherical, about ⅛ inch long, green, with the style persisting visibly on the tip. They usually contain 4 seeds.
Similar species: One other Physaria species, spreading bladderpod (Physaria gracilis), occurs in Missouri. Unlike Missouri bladderpod, spreading bladderpod does not have a silvery-gray appearance, the basal and stem leaves are similar in shape, and it does not occur within the range of Missouri bladderpod.
Height: 4 to 8 inches.
Missouri bladderpod is presently found in the following southwest Missouri counties: Dade, Greene, Christian, and Lawrence.
Habitat and Conservation
Occurs on limestone glades and rocky outcroppings. Many populations have persisted in grazed pastures, rocky open woods, and limestone outcrops along roadsides.
Conservation efforts involve conservation of the habitat bladderpod requires. Glades are open habitats that are easily invaded by eastern red cedar and other woody plants. Before European settlement, glades were prevented from turning into woods by naturally occurring wildfires. Today, land management replicates the natural cycle of natural fires using controlled burns.
Other threats to bladderpod and its habitat include invasive species, mining, development of roads, homes, and other construction, protection from herbicides, and off-road vehicles.
Protected populations are being managed at Wilson’s Creek National Battlefield (National Park Service), Rocky Barrens Conservation Area (Missouri Department of Conservation), Greenfield Glade (The Nature Conservancy), and Bois d’Arc Conservation Area (Missouri Department of Conservation). Nearly all remaining sites are on privately owned land.
Status
A species of conservation concern: listed as endangered in Missouri and threatened federally.
Missouri holds most of the populations of this rare wildflower, where it occurs only in limestone glades in the southwestern part of the state.
Populations of this attractive annual undergo wide fluctuations from year to year in the number of plants present. Many of the glades where it grows have been heavily impacted by quarrying, grazing, construction, and/or fire suppression. Fortunately, some populations are growing on protected lands.
Life Cycle
Flowers from April to May, producing 4-petaled, bright yellow blossoms clustered at the tops of the stems. The small (⅛ inch diameter), round green fruits appear from May to early June and gradually turn brown. Each fruit contains 4 flattened brown seeds. These drop in late May and early June, lie dormant through summer, and germinate in fall. They grow in a rosette, which appears as a tiny, button-sized cluster of leaves, and remains throughout the winter until spring.
Human Connections
Many consider wildflowers the jewels of nature’s garden, and far more valuable than human-made horticultural varieties.
An oil can be made from the seeds of various species of bladderpods that can be used for manufacturing resins, waxes, plastics, coatings, and more.
Ecosystem Connections
Limestone glades, where this species grows, are home to an attractive and interesting group of plants and animals that live nowhere else in our state. In order to save this species, we must first protect its habitat. In the process, we help all the other organisms in that habitat.
