CU Botanist’s Notes on a Nightshade
To ecology and evolutionary biology professor Stacey D. Smith, the research subjects she has dedicated 25 years of her life to studying are completely adorable. And, after hearing her eagerly discuss her work on tomatillos in the Solanaceae family — commonly known as nightshades — passersby may find the diminutive plants irresistible, too.
Smith is one of only a handful of scientists to study the wild members of this plant family, which includes over 300 species in the tomatillo tribe. Her lab studies the evolutionary changes of the plants’ flowers and fruits, including how and why their colors and shapes have changed over time, and her work with the tomatillo plants’ smallest details, from their minuscule stem hairs to their fruits’ sticky residue, might someday help in the creation of natural pesticides.
“I want to understand why plants do the things they do, and why they live the way they do,” Smith said.
Physalis heterophylla
→ Native
One of the four native Boulder tomatillos: heterophylla, hederifolia, longifolia and virginiana.
→ Clammy
Called “clammy” because of the sticky hairs on its stems and leaves.
→ Habitat
Can be found on hiking trails along the Front Range: Sanitas Valley, Saddle Rock, Skunk Canyon and the Shanahan Ridge Water Tank.
Tomatillo Facts
Toxic
The plants are toxic, but some of their fruits are edible to humans.
Nightshades
The plants are part of the nightshade family, Solanaceae, which has about 2,700 species.
Greenhouse Plants
About 100 tomatillos and their relatives are growing in CU Boulder’s main campus greenhouses.
Difficult Cultivation
The plants are hard to cultivate, but grow well in the wild.
Delicate in Nature
The plants don’t recover well when mowed over and are easily overrun by non-native plants.
Physalis heterophylla Fruit
Lanterns
When fruit forms, the plant creates a lantern around it to protect it from insects.
Ground Cherries
The edible fruits, referred to as “ground cherries,” are orange and high in vitamin A.
Illustration by Irene Laschi