Mercer Gardens Herbarium Provides Glimpse into the Past

Did you know that Mercer Botanic Gardens offers more than stunning garden views? Behind the scenes, Mercer has a thriving research center boasting a growing collection of pressed and dried plant samples, known to botanists as a herbarium.

Mercer’s herbarium collection started in 1986 and is now located at the Mercer Botanical Center on Titlelist Drive just across Cypress Creek. As of this year, Mercer’s herbarium includes more than 50,000 plant specimens on long-term loan from the Spring Branch ISD Science Center (SBSC).

Dr. Larry Brown, a local botanist, was instrumental in expanding both collections over the years and transferring the SBSC collection to Mercer. This combined collection specializes in Houston metropolitan flora and particularly rare flora from unique saline prairies found in Harris County and other parts of East Texas.

In many ways, a herbarium is like a history book. Each specimen can last indefinitely after it is pressed, dried, and mounted on acid-free paper in climate- and pest-controlled conditions. Researchers can use these preserved plant specimens to reference extinct species or document when plants hybridize and create new genetic lines. While living plants may be short-lived, properly preserved herbarium specimens offer a permanent record that can last for centuries. One of the oldest herbarium collections dates back to 1532!

A herbarium is a critical component in identifying a plant’s geographic location and environment at the time it was collected. Over time, this information can show how plant populations shift as the climate changes. Other entries may show when seeds can be harvested, making this a valuable resource for stocking seed conservation banks.

Taxonomists often extract and study DNA from specimens to determine plant similarities on a genetic level. DNA analysis can reveal relationships between plants not visible under microscopes. Botanical artists and researchers also use herbarium specimens as reference material for identifying plants and creating botanical illustrations.

Maintaining these samples for future generations is a full-time job. Fortunately, Mercer has skilled botanists and a team of dedicated interns and volunteers who carry out this important work. Thank you to all the volunteers who are helping develop and maintain Mercer’s collection!