Hedeoma todsenii
Encyclopedia
Hedeoma todsenii is a rare species of flowering plant in the mint family
known by the common name Todsen's pennyroyal, or Todsen's false pennyroyal. It is endemic to New Mexico
in the United States, where it occurs in the San Andres
and Sacramento Mountains. It is federally listed as an endangered species
of the United States.
This plant was discovered on the White Sands Missile Range
in 1978 by Thomas K. Todsen and described to science and named for him the following year. It is a rhizomatous
perennial herb growing up to 20 centimeters tall with fragrant lance-shaped leaves. The tubular flowers are red-orange or occasionally yellow in color and bloom in the summer rainy season. Flowers occur rarely, with only 20% of the plants flowering in a given season. The plant reproduces vegetatively
, forming wide mats of many clones
all arising from the rhizome of one plant. What appears to be a large colony of many stems may actually be a single plant.
The plant grows on steep mountain slopes composed of gypsum
and limestone
. It occurs in pinyon-juniper woodland habitat dominated
by the Colorado Pinyon
(Pinus edulis) and one seed juniper
(Juniperus monosperma). It grows among grasses such as muhly grass
(Muhlenbergia sp.) species. It occurs in shady spots in the habitat where moisture remains for a longer period of time. The rare plant may be a relict species
from a time when the region was cooler and not as dry.
There are three occurrences of the plant in the San Andres Mountains and fifteen occurrences in the Sacramento Mountains. The plant, as a relict, may be naturally rare. It reproduces by cloning itself. Flowering occurs rarely, and successful seed set is relatively uncommon. Few pollinator
s visit the flowers. When a plant does produce fruit, it usually produces only one or two nutlets together, instead of the quartet that is possible. Furthermore, most of the seeds do not germinate
.
Threats to the species include its low reproductive rate and genetic diversity
, illegal grazing
of domestic animals, and damage from insect
s and other wild animals.
Lamiaceae
The mints, taxonomically known as Lamiaceae or Labiatae, are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae...
known by the common name Todsen's pennyroyal, or Todsen's false pennyroyal. It is endemic to New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
in the United States, where it occurs in the San Andres
San Andres Mountains
The San Andres Mountains are a mountain range in the southwestern U.S. state of New Mexico, in the counties of Socorro, Sierra, and Doña Ana. The range extends about 75 miles north to south, but are only about 12 miles wide at their widest...
and Sacramento Mountains. It is federally listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of the United States.
This plant was discovered on the White Sands Missile Range
White Sands Missile Range
White Sands Missile Range is a rocket range of almost in parts of five counties in southern New Mexico. The largest military installation in the United States, WSMR includes the and the WSMR Otera Mesa bombing range...
in 1978 by Thomas K. Todsen and described to science and named for him the following year. It is a rhizomatous
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
perennial herb growing up to 20 centimeters tall with fragrant lance-shaped leaves. The tubular flowers are red-orange or occasionally yellow in color and bloom in the summer rainy season. Flowers occur rarely, with only 20% of the plants flowering in a given season. The plant reproduces vegetatively
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
, forming wide mats of many clones
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
all arising from the rhizome of one plant. What appears to be a large colony of many stems may actually be a single plant.
The plant grows on steep mountain slopes composed of gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
and limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
. It occurs in pinyon-juniper woodland habitat dominated
Dominant species
Dominant species may mean:*Dominant species , one of a small number of species which dominate in an ecological community*Dominant Species by Michael E. Marks*Dominant Species...
by the Colorado Pinyon
Colorado Pinyon
The Colorado Pinyon, Two-needle Pinyon, or Piñon Pine, ', is a pine in the pinyon pine group whose ancestor was a member of the Madro-Tertiary Flora and is native to the United States....
(Pinus edulis) and one seed juniper
Juniperus monosperma
Juniperus monosperma is a species of juniper native to western North America, in the United States in Arizona, New Mexico, southern Colorado, western Oklahoma , and western Texas, and in Mexico in the extreme north of Chihuahua...
(Juniperus monosperma). It grows among grasses such as muhly grass
Muhlenbergia
Muhlenbergia is a genus of grass in the Poaceae family. It is named in honour of the American amateur botanist Gotthilf Heinrich Ernst Muhlenberg. There are around 155 species. Many are known by the common name muhly....
(Muhlenbergia sp.) species. It occurs in shady spots in the habitat where moisture remains for a longer period of time. The rare plant may be a relict species
Relict
A relict is a surviving remnant of a natural phenomenon.* In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas....
from a time when the region was cooler and not as dry.
There are three occurrences of the plant in the San Andres Mountains and fifteen occurrences in the Sacramento Mountains. The plant, as a relict, may be naturally rare. It reproduces by cloning itself. Flowering occurs rarely, and successful seed set is relatively uncommon. Few pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s visit the flowers. When a plant does produce fruit, it usually produces only one or two nutlets together, instead of the quartet that is possible. Furthermore, most of the seeds do not germinate
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
.
Threats to the species include its low reproductive rate and genetic diversity
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
, illegal grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
of domestic animals, and damage from insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and other wild animals.