''Thelocactus bicolor'', the glory of Texas, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the cactus

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

, widely distributed in the northern Chihuahuan Desert of

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

and

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Description

Plants are usually solitary, but may form clumps. It typically grows to about 6 to 10 centimeters in diameter, growing to tall, it is a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

with succulent stems with a blue or gray-green body that is somewhat felty at the top and often thorny. The cactus has 8 to 13 straight or twisted ribs, each divided into crookedly truncated cusps up to 1.5 centimeters high. It also has 9 to 18 marginal spines that are protruding or slightly curved and up to 3 centimeters long, as well as 1 to 4 central spines that are all up to 3 centimeters long. The central spines are brightly colored, white or reddish in the middle, or red at the base and yellow at the tip, gradually becoming grayish with age. The lowest central spine is stretched out and prim, while the upper ones are erect and flat. Large daisy-like flowers, in diameter with ciliate edges, are borne in summer. The petals are purplish-pink, fading to white. The inner petal tips form a circle of red surrounding a prominent yellow boss. The fruits are reddish-brown, scaly, and edible.

Distribution

These plants are primarily found in the northern Chihuahuan desert in

and Mexico (Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Tamaulipas, Zacatecas) at elevations of 800-2200 meters. They typically grow on flat gravelly soils, limestone or sandstone slopes of hills or outcrops, and alluvial fans in desert or grassland environments.

Taxonomy

The first description of ''Thelocactus bicolor'' was made in 1848 by

Ludwig Karl Georg Pfeiffer Ludwig Karl Georg Pfeiffer, also known as Louis Pfeiffer (4 July 1805 – 2 October 1877), was a German physician, botany, botanist and conchology, conchologist. Early life, education and medical career Pfeiffer was born in Cassel, the eldest so ...

. The specific epithet "bicolor" comes from Latin, meaning 'two-colored,' and refers to the two-colored flowers of the species.

Nathaniel Lord Britton Nathaniel Lord Britton (1859 – 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York (state), New York. Early life Britton was born on the 15 of January 1859 at New Dorp, Staten Island ...

and

Joseph Nelson Rose Joseph Nelson Rose (January 11, 1862 – May 4, 1928) was an American botanist. He was born in Union County, Indiana. His father died serving during the Civil War when Joseph Rose was a young boy. He later graduated from high school in Liberty, ...

placed the species in the genus ''Thelocactus'' in 1922.

Subspecies

Accepted Subspecies

Cultivation

This cactus is grown as an ornamental. A warm, dry, sunny spot in sharply-drained specialist cactus compost must be provided. It has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

Gallery

File:ThelocactusBicolor.jpg , ''Thelocactus bicolor'' File:Thelocactus bicolor v. tanquecillos (14686836828).jpg, ''Thelocactus bicolor'' v. ''tanquecillos'' File:Thelocactus bicolor - Stempel und Staubgefäße (14379643272).jpg, Pistil and stamens File:Thelocactus bicolor 1.jpg, ''Thelocactus bicolor''

References

External links

* * {{Taxonbar, from=Q150224 bicolor Flora of Mexico Least concern plants Plants described in 1922