''Amsonia tharpii'' is a species of flowering plant in the family

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

known by the common names Tharp's bluestar and feltleaf bluestar. It is native to

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the United States.''Amsonia tharpii''.
Center for Plant Conservation. This plant is a perennial herb with a woody

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

. It grows up to about 20 centimeters tall. The linear to lance-shaped leaves are each up to 3 centimeters long and are whorled about the stem. The leaves lower on the plant are wider than those near the top.''Amsonia tharpii''.
New Mexico Rare Plants. The white, pale blue,''Amsonia tharpii''.
The Nature Conservancy. or greenish flowers are borne in clusters at the stem tips. They are tubular and about 1.5 centimeters long. The fruit is a two-lobed follicle. The cylindrical seeds are about a centimeter long. There are three populations of this plant in New Mexico in Eddy County, and there is a single population in Texas, in

Pecos County Pecos County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 15,193. The county seat is Fort Stockton. The county was created in 1871 and organized in 1875.. By Glenn Justice and John Leffler. Retriev ...

. The New Mexico and Texas sites are over 160 kilometers apart. The plant is probably a

relict species In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a ...

, rare now that conditions have changed since it was more abundant. Today it grows on

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

and

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...

substrates in

Chihuahuan Desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lower P ...

scrub vegetation. The plant is threatened by the loss and degradation of its habitat. In New Mexico it is threatened by oil and gas development and the changes that have occurred on the land due to

overgrazing Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature res ...

, such as

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

and

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

of plants. In Texas, the plant grows on roadsides and it may be threatened by roadway maintenance.

References

External links

USDA Plants Profile
{{Taxonbar, from=Q4748805 tharpii Flora of New Mexico Flora of Texas