Todsen's Pennyroyal

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Todsen's Pennyroyal

Hedeoma todsenii

ListedJanuary 19, 1981
FamilyLamiaceae (Mint)
DescriptionPerennial herb with small, opposite leaves and orange-red flowers.
HabitatCanyon slopes of loose gypsum and limestone gravel.
ThreatsFragile habitat, low numbers.
RangeNew Mexico


Todsen's pennyroyal, Hedeoma todsenii, is a perennial herb that grows to a maximum height of about 8 in (20 cm). It has a somewhat woody base and opposite, lance-shaped leaves, only about 0.6 in (1.5 cm) long. Solitary orange-red flowers appear in August and may continue blooming through September. Seeds germinate in the fall near the end of the rainy season. The plant is pollinated by moths, bees, butterflies, and possibly hummingbirds. This pennyroyal may be capable of inbreeding.


Todsen's pennyroyal grows on steep, north-facing, moderately steep canyon slopes in loose gypsum and limestone gravel at elevations between 6,100-6,600 ft (1,800-2,000 m). It occurs within a plant community dominated by one-seeded juniper, pinyon pine, and Muhly grass. Rainfall averages about 25 cm (10 in) per year. It seems to prefer open sites with a low canopy cover.


Todsen's pennyroyal is endemic to the San Andres Mountains of southern New Mexico. It is restricted to two known populations on the White Sands Missile Range (Sierra County), New Mexico, which is administered by the U.S. Army. Each population, comprising about 500 stems, is spread over an area of about 11.5 sq mi (30 sq m). Because this mint propagates by rhizomes, it is difficult to know when plants within a population are separate or simply multiple clones of a single plant. The actual number of plants was estimated at about 750 in 1985.


What originally brought about the decline of Todsen's pennyroyal is unknown. The habitat is extremely fragile and suffers from periodic flash floods, which disturb the slopes and cause localized erosion.

While the plant's remote locations and the restricted nature of the White Sands Missile Range provide some protection, its small numbers make it vulnerable to some cataclysmic event. Even minor changes in land use in its canyon sites could threaten its existence.

Conservation and Recovery

Since the plant's listing as endangered in 1981, the Army has agreed to consult with the Fish and Wildlife Service, concerning any activities, such as large-scale troop maneuvers or road construction, that might jeopardize the plant or its habitat.


U.S. Fish and Wildlife Service
Division of Endangered Species
P.O. Box 1306
Albuquerque, New Mexico 87103


Irving, R. S. 1979. "Hedeoma todsenii (Labiatae), a New and Rare Species from New Mexico." Modrono 26(4):184-187.

Irving, R. S. 1980. "Hedeoma todsenii Status Report." Report. U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1985. "Todsen's Pennyroyal (Hedeoma todsenii ) Recovery Plan." U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1987. "Endangered and Threatened Species of Arizona and New Mexico (with 1988 Addendum)." U.S. Fish and Wildlife Service, Albuquerque.