Garden Closed

The United States Botanic Garden (USBG) is temporarily closed to the public to reduce the risk of transmitting COVID-19 coronavirus.

Whenever possible, the USBG will reschedule public programs and events originally scheduled during the closure period. Please monitor the USBG website for updates to operating status. Many resources can still be accessed online, including educational worksheets and manuals, fact sheets and more, and some of our programs will also be made available online. Find online resources at

Old woman cactus

Mammillaria hahniana (Old woman cactus)
Plant Botanical Name: 
Mammillaria hahniana
USBG Plant Location: 
Conservatory Room Location: 
World Deserts
Plant Threat Level: 

Mammillaria hahniana is commonly known as the old woman cactus because of the grayish hairs that protect it from the harsh sun common to its native habitat in the Mexican state of Guanajuato. Mexico is an important center of diversity for the Cactus family, containing more than 500 species and possessing the highest number of endemic and endangered cacti of any country in the world. Though wild populations of Mammillaria hahniana are still considered vulnerable, widespread propagation of this species by commercial nurseries catering to cactus hobbyists has greatly reduced the demand for plants illegally collected from naturally occurring populations.