''Allionia'', commonly known as windmills or trailing four o'clock, is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of two plant species widespread in the Western Hemisphere. Both species are unusual in their blooms, which consist of three separate flowers appearing to be a single flower. The plants are finely

pubescent The adjective pubescent may describe: * people or animals undergoing puberty * plants that are hairy, covered in trichomes * insects that are covered in setae In biology, setae (; seta ; ) are any of a number of different bristle- or hair-lik ...

annuals or short-lived perennials, with trailing, recumbent stems up to one metre in length, often threading through other vegetation. The leaves range from oval to oblong, under 4 cm long. The inflorescences are

axillary Axillary means "related to the axilla (armpit)" or "related to the leaf axils". "Axillary" may refer to: Biology * Axillary artery * Axillary border * Axillary fascia * Axillary feathers * Axillary hairs * Axillary lines * Axillary lymph nodes ...

, consisting of three flowers with petals varying in color from red to purple, symmetrically arranged and superficially appearing to be a single flower 3–15 mm across. The individual flowers are bisexual and bilaterally symmetric with a distinct oblique funnel. The 5–7

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s may be somewhat exserted, along with the

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

. The boat-shaped anthocarps are morphologically distinct from those of other members of their family. These fruits have five ribs and two rows of inward pointing teeth on the concave side. Molecular evidence supports ''Allionia'' as sister to the least inclusive clade containing both ''

Boerhavia ''Boerhavia'' is a genus of over 100 species in the Nyctaginaceae family. The genus was named for Herman Boerhaave, a Dutch botanist, and the genus name is frequently misspelled "''Boerhaavia''". Common names include spiderlings and hogweeds. Ta ...

'' and ''Cyphomeris.'' The range of '' Allionia incarnata'' L. includes

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, the

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

, while '' Allionia choisyi'' Standley is more restricted in North America, occurring only in

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, and

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 ...

. The two species can only be reliably distinguished by characteristics of their fruits, and even those may be found intergraded where the species' ranges overlap.

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

named the genus after Italian botanist

Carlo Allioni Carlo Allioni (23 September 1728 in Turin – 30 July 1804 in Turin) was an Italian physician and botanist, professor of botany at the University of Turin. His most important work was ''Flora Pedemontana, sive enumeratio methodica stirpium indi ...

(1725–1804).

References

Flora of North America: ''Allionia''
Nyctaginaceae genera Taxa named by Carl Linnaeus Nyctaginaceae {{Caryophyllales-stub