''Allenrolfea'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of shrubs in the family

Amaranthaceae Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus ''Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it ...

. The genus was named for the English botanist

Robert Allen Rolfe Robert Allen Rolfe (1855, Wilford, Nottinghamshire – 1921, Richmond, Surrey) was an English botanist specialising in the study of orchids. For a time he worked in the gardens at Welbeck Abbey. He entered Kew in 1879 and became second assistant. ...

. There are three species, ranging from North America to South America.

Description

The species of ''Allenrolfea'' are

subshrub A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...

s or

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s with erect or decumbent growth. The stems are much branched, succulent, glabrous and appear to be articulated. The alternate

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are sessile and stem-clasping, fleshy, glabrous, their blades reduced to small, broadly triangular scales, with entire margins and acute apex. The inflorescences are terminal spikes with spirally arranged flowers.

Cymes An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on ...

of three or five flowers are sitting in the axils of deciduous, peltate, fleshy

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s. The flowers are bisexual. The perianth consists of 4-5 joined

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s, their lobes angled and truncate distally. There are 1-2

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s exserting the flower and an ovary with 2(-3) stigmas. The fruit in an ovoid, compressed utricle with membranous

pericarp Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggre ...

. The erect

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

is brown or reddish brown, oblong, with smooth surface. It contains copious

perisperm In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fe ...

(feeding tissue), and a half-annular embryo. The chromosome basic number is x = 9.

Occurrence

The species of ''Allenrolfea'' are distributed in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

(southwestern United States), Mexico,

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

(

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

). They grow on

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a base (chemistry), basic, ionic compound, ionic salt (chemistry), salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as ...

soils, on sandy hummocks in salt playas, and in mud flats. In the USA they are found at about 1000–1700 m above sea level.

Systematics

The first publication of the genus ''Allenrolfea'' was made in 1891 by

Otto Kuntze Carl Ernst Otto Kuntze (23 June 1843 – 27 January 1907) was a German botanist. Biography Otto Kuntze was born in Leipzig. An apothecary in his early career, he published an essay entitled ''Pocket Fauna of Leipzig''. Between 1863 and 1866 he ...

. With this description, he replaced the invalid name ''Spirostachys'' from 1874, (which is illegitimate, as ''

Spirostachys ''Spirostachys'' is a plant genus of the family Euphorbiaceae first described as a genus in 1850. It is native to Africa.Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A. (2000). World Checklist and Bibliography of Euphorbiaceae (and Pandaceae) 1- ...

'' already existed since 1850). The type species is ''Allenrolfea occidentalis''. The genus consists of three species: *''

Allenrolfea occidentalis ''Allenrolfea occidentalis'', the iodine bush, is a low-lying shrub of the Southwestern United States, California, Idaho, and northern Mexico.Shultz, L.M.: 'eFloras 2008''Allenrolfea occidentalis'' in Flora of North America Missouri Botanical Ga ...

'' , in North America (southwestern USA: Arizona, California, Idaho, New Mexico, Nevada, Oregon, Texas, Utah), and in Mexico. *''

Allenrolfea patagonica ''Allenrolfea'' is a genus of shrubs in the family Amaranthaceae. The genus was named for the English botanist Robert Allen Rolfe. There are three species, ranging from North America to South America. Description The species of ''Allenrolfea' ...

'' ,

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

. *''

Allenrolfea vaginata ''Allenrolfea'' is a genus of shrubs in the family Amaranthaceae. The genus was named for the English botanist Robert Allen Rolfe. There are three species, ranging from North America to South America. Description The species of ''Allenrolfea' ...

'' , endemic to Argentina. ''Allenrolfea'' is a near relative of the genus ''

Heterostachys ''Heterostachys'' is a genus of flowering plants in the plant family Amaranthaceae. The two species are shrubby halophytes native to South America and Central America. Description The species of ''Heterostachys'' grow as subshrubs or low shr ...

'', which also is distributed in America. Their common lineage seems to have evolved early in the evolution of the subfamily

Salicornioideae The Salicornioideae are a subfamily of the flowering plant family Amaranthaceae (''sensu lato'', including the Chenopodiaceae). Important characters are succulent, often articulated stems, strongly reduced leaves, and flowers aggregated in thick, ...

, dating back to the Early to Middle

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

. It might have reached America long before the other American taxa of Salicornioideae.

References

Kadereit, G., Mucina, L., & Freitag, H.: ''Phylogeny of Salicornioideae (Chenopodiaceae): diversification, biogeography, and evolutionary trends in leaf and flower morphology'', In: ''Taxon'', Volume 55 (3), 2006, p. 624, 635. Kuntze, C.E.O.: ''Revisio Generum Plantarum'' 2, 1891, p. 545-546
first description scanned at BHL
/ref> Shultz, L.M.: 'eFloras 2008
''Allenrolfea'' in Flora of North America
Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA. F.O. Zuloaga, O. Morrone, M.J. Belgrano, C. Marticorena, E. Marchesi. (Hrsg.) 2008. ''Catálogo de las plantas vasculares del Cono Sur.'' Monogr. Syst. Bot. Missouri Bot. Gard. 107(1–3): i–xcvi, 1–3348
''Allenrolfea patagonica''
F.O. Zuloaga, O. Morrone, M.J. Belgrano, C. Marticorena, E. Marchesi. (Hrsg.) 2008. ''Catálogo de las plantas vasculares del Cono Sur.'' Monogr. Syst. Bot. Missouri Bot. Gard. 107(1–3): i–xcvi, 1–3348
''Allenrolfea vaginata''

External links

* *
USDA Plants Profile

Illustration of ''Allenrolfea patagonica'' at ''Instituto de Botanica Darwinion''

Illustration of ''Allenrolfea vaginata'' at ''Instituto de Botanica Darwinion''
{{Taxonbar, from=Q3736031 Amaranthaceae Amaranthaceae genera