TODAY’S HOURS: 8 am – 6 pm 

Floral illustration from 1829 of stemless evening primrose

What Is This Thing? Discovering Stemless Evening Primrose.

Cynthia sent us photos of this dried object and asked, “What is this thing?”

It’s one thing to identify a flower when it’s in bloom. Petals, stamens and other features provide all sorts of information to botanists to narrow down the plant’s name and history.

Starting with a seed pod is a different matter – especially when the pod is hard, dried, and an indistinct brown. When friends Carol and Cynthia both found particularly tough, dried pods that superficially resemble pine cones, they were baffled.

But it takes more than a dried-up pod to baffle the botanists at the BRIT Herbarium. They were able to let Cynthia and Carol know that they had found the dried fruits of Oenothera triloba, or stemless evening primrose.

This is not the first time stemless evening primrose has been brought to the attention of our botanists, and one of our researchers wrote an article about it in 2018.

“A winter annual, this native wildflower comes up in disturbed places (and often lawns) at the end of the year, overwinters as a rosette, then produces yellow flowers in the spring,” wrote Brooke Best, director of research programs. “Flowers arise from the base of the plant, meaning fruit eventually develop at the base as well. As the soft green parts of the plant die away, these tough bunches of fruit are left behind at ground-level. (And I do mean tough, so watch your step!)”

Best also explained that, though the species itself is widely distributed across the eastern-to-southeastern part of the country, its distribution is patchy, and the plant is uncommon throughout its range. “It’s even considered threatened in Kentucky and extirpated (locally extinct) in Indiana,” wrote Best.

Stemless evening primrose usually volunteers in lawns, but some people grow it their gardens and enjoy watching the flowers open at sunset.

The blooms of Oenothera speciosa are yellow and white in the center and turn a cheerful pink along the edges.
Oenothera speciosa or pink evening primrose is found every spring blooming alongside Texas highways.

Oenothera triloba is related to other varieties of evening primrose. The most well-known of these plants in Texas is pink evening primrose or Mexican evening primrose, aka Oenothera speciosa. This plant produces masses of pale pink blooms that shade into yellow at the center. The yellow pistils are covered with powdery pollen, contributing to the other common name “buttercups.” (True buttercups are members of the plant genus Ranunculus.) The Texas Department of Transportation sows this plant along roadsides, and it can be spotted alongside other wildflowers every spring.

Another variety of evening primrose is Oenothera biennis or common evening primrose. This biennial plant produces yellow flowers on an upright stalk that can reach 7 inches tall. Oenothera biennis is well known for an oil produced from its seeds. Evening primrose oil is widely used to treat PMS symptoms, some arthritis-related conditions, and eczema, although scientific evidence to support these uses is lacking.

If you have a plant, or a pod, that you can’t identify, remember that you can always turn to the botanical experts at FWBG | BRIT. We play “What Is This Thing?” in the newsletter about once a quarter, but you can also submit plants any time to the BRIT Herbarium for identification. Read more about it, including how to request an identification and the information we ask you to provide along with your plant.

Thanks to Cynthia and Carol for their submission. Our botanists travel the world to study plants, but there is much to learn exploring the mysteries of our own backyard.

Related Articles


Celebrate Hispanic Heritage with Your Family during a Full Day of Activities at the Garden

Our four-week festival of Hispanic heritage, ¡Celebramos!, begins Sept. 15, and our calendar is packed with events that range from a Quinceañera community celebration to an outdoor market to an art exhibit of depictions of the plants of Latin America. Families looking to celebrate Hispanic Heritage with their children should highlight Saturday, Oct. 1 on their calendars and plan to attend Día de la Familia. The day is packed with educational programs and performances and culminates with movie night at the Garden.

Read More »
A field of yellow sunflowers

Making Sense of Sunflowers

The natural world is filled with flowers of all shapes and colors. What’s surprising is that a great many of these flowers are all related. About one quarter of flowering plants are members of the Asteraceae family, which contains more than 32,000 known species of flowering plants. The sheer variety of sunflowers can make the plant a challenge to identify. Yet correctly identifying Asteraceae is important when conducting plant surveys, assessing the ecological health of a habitat, managing land or simply exploring nature. Fortunately, sunflower experts Richard Spellenberg and Naida Zucker can help. Join us for their book talk and workshop on sunflowers and never be confounded by sunflowers again.

Read More »
Multicolored kernels on heritage corn

Ethnobotany and the Study of Plants, Cultures and Communities

Imagine you lived exactly where you live today–but five hundred years ago. If you’re hungry, you can’t go to the grocery store. If you’re tired, you no longer have a foam mattress. If you have a headache, you can’t pop an Advil. Yet the people of the past ate, slept and treated their ailments just as we do. How? They used plants.

Read More »
Yellow tulilps against green foliage

Plan Now for Bountiful Bulbs Next Spring

A sigh of relief can be heard across North Texas that the heat wave has broken. We know to expect more hot days in September, but with Labor Day behind us, cooler weather is just around the corner. That means it’s time to think about spring! No, we’re not crazy, and yes, we know it’s not yet autumn. But now is the time to plan for a gorgeous spring by planting bulbs.

Read More »
Sunflowers by sign that reads Embrace New Beginnings

Community Education Fall Preview: Grow Your Mind with New Classes and Workshops

It still feels like the height of summer, but fall is just around the corner, and that means the Community Education program is rolling out a new slate of classes, workshops and events. “We’ve got a mix of long-time favorites and completely new experiences,” says Community Education Manager Crissa Nugen. “I think almost everyone will find something they want to explore.”

Read More »
Water sprinkler on summer day

Managing Your Garden Through Heat and Drought

Gardeners across North Texas can only look at their landscape and sigh as the heat wave refuses to break and rain refuses to fall. Plants that thrive most summers are withering and dying under the stress of week after week of 100-degree-plus temperatures. Gardeners struggle to balance watering enough to keep their plants alive with responsible behavior during a drought–and the prospect of budget-busting water bills. What to do? “The first step is to not give up,” says Sr. Horticulturist Steve Huddleston. “You do have options.”

Read More »