Rare Plant Projects

Saguaro National Park was established in 1933 specifically to protect an impressive stand of many large saguaro cacti – the “Cactus Forest” – at the base of the Rincon Mountains east of Tucson, Arizona. However, concerns about the decline of the Cactus Forest have been expressed throughout the history of the park. As a result, research on saguaros in the park began as early as 1939 and continues to this day.

The tiny, federally endangered sentry milk-vetch (Astragalus cremnophylax var. cremnophylax) is a perennial herb that forms a one inch tall by eight inch wide mat in shallow pockets of soil on the Kaibab limestone. It is endemic to the Grand Canyon, and only grows within 25 feet of the canyon rim. Since 2006, when the Sentry Milk-Vetch Recovery Plan was completed, Grand Canyon National Park has partnered with other groups to help reverse the decline of this species.