Hedeoma todsenii

Todsen's Pennyroyal

FWS Focus

Overview

Characteristics
Overview

Todsen’s pennyroyal is a mint endemic to the limestone-gypseous soils of the San Andres Mountains and Sacramento Mountains in Sierra and Otero Counties of New Mexico.  This species was discovered in 1978, named in 1979, and listed as endangered (with critical habitat) in 1981. This species mainly reproduces asexually, but flowers can be pollinated by broad-tailed hummingbirds. According to the 2011 5-year review of this species, major threats to the species include climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change
, increasing piñon-juniper woodland densities (which increases the threat of wildfire), and its inherent genomic constraints to sexual reproductive success and dispersal.

Scientific Name

Hedeoma todsenii
Common Name
Todsen's pennyroyal
Todsen's false pennyroyal
FWS Category
Flowering Plants
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Todsen’s pennyroyal is one of the many habitat specialists in the hot and arid New Mexico. It grows in gypseous-limestone soils on the northern facing slopes of the San Andres and Sacramento Mountains in New Mexico. The gypseous-limestone soils that Todsen’s pennyroyal inhabits are associated with the Yeso formation (a geologic formation which dates back to the Permian period). These gypseous soils are able to retain more moisture than surrounding substrates. These specific habitat characteristics provide the cool, moist, microclimate that is required for this species.

Populations in the San Andres Mountains:

  • commonly occupy pinyon-juniper woodlands
  • range in tree cover from as low as 10% cover to as high as 50% cover
  • inhabit lower elevations than Sacramento Mountains populations, with populations ranging from 6263 feet to 7404 feet (1909 meters to 2257 meters)

Populations in the Sacramento Mountains:

  • predominantly occupy pinyon-juniper woodlands, but can also be found in scattered ponderosa pine, and Douglas-fir woodlands
  • range in tree cover from as low as 10% cover to as high as 70% cover
  • inhabit higher elevations than San Andres Mountains populations, with populations ranging from 6178 feet to 6873 feet (1883 meters to 2095 meters)
Forest

A dense growth of trees and underbrush covering a large tract.

Mountain

A landmass that projects conspicuously above its surroundings and is higher than a hill.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

Todsen’s pennyroyal is a perennial, rhizomatous herb that stands 4 to 8 inches (10 to 20 centimeters) tall and is woody at the base. Todsen’s pennyroyal, specifically possesses the following:

  • Slender and unbranched rhizomes below the soil surface
  • Opposite, lance-shaped, smooth margined leaves, 0.3 to 0.6 inches (0.8 to 1.5 centimeters) long and 0.1 to 0.2 inches (0.25 to 0.5 centimeters) wide
  • Tubular flowers are solitary and located at the upper portion of the stems. The flowers contain five united petals and are 1.4 inches (3.6 centimeters) in length. The calyx, which surrounds the base of the flower, is 0.5 inches (1.3 centimeters) in length. Each flower possesses two stamens
  • Up to four nutlets, nutlets are around 2 mm wide and 1 mm wide  
Color & Pattern

Todsen’s pennyroyal flowers are usually an orange-red color, but yellow flowers have been observed in the Sacramento Mountains populations. The insides of the flowers are streaked. Nutlets are dark brown in color. The stems and leaves of Todsen’s pennyroyal are a dark green color.  

Geography

Characteristics
Range

Todsen’s pennyroyal is limited to the San Andres Mountains and Sacramento Mountains in New Mexico. At the time the species was listed, in 1981, it was only known from two locations in the San Andres Mountains on White Sands Missile Range. As we learn more about the species, there have been increased survey efforts in suitable habitat, these surveys have consistently revealed additional populations.

Since Todsen’s pennyroyal’s discovery, a total of 47 populations have been discovered:

  • 32 populations in the Sacramento Mountains in Otero County

  • 15 in the San Andres Mountains in Sierra County

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