''Boechera'' (rockcress) 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 the family

Brassicaceae Brassicaceae () or (the older) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The le ...

. It was named after the

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

botanist

Tyge W. Böcher Tyge Wittrock Böcher (25 October 1909 – 15 March 1983) was a Danish botanist, evolutionary biologist, plant ecologist and phytogeographer. He was born in Copenhagen to physician Einar Böcher and wife Cathinca née Andersen. ''Steen B. Böc ...

(1909–1983), who was known for his research in alpine plants, including the mustards ''

Draba ''Draba'' is a large genus of flowering plants in the family Brassicaceae, commonly known as whitlow-grasses (though they are not related to the true grasses). Species There are over 400 species: *'' Draba abajoensis'' Windham & Al-Shehbaz *'' ...

'' and ''Boechera holboellii''. According to recent molecular-based studies, ''Boechera'' is closely related to the genus ''

Arabidopsis ''Arabidopsis'' (rockcress) is a genus in the family Brassicaceae. They are small flowering plants related to cabbage and mustard. This genus is of great interest since it contains thale cress (''Arabidopsis thaliana''), one of the model organi ...

'' which also includes the widely known model plant ''

Arabidopsis thaliana ''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. ''A. thaliana'' is considered a weed; it is found along the shoulders of roads and in disturbed land. A winter a ...

''. Until recently, members of this genus were included in the genus ''

Arabis ''Arabis'' ,''Sunset Western Garden Book,'' 1995:606–607 or rockcress, is a genus of flowering plants, within the family Brassicaceae. Description The species are herbaceous, annual or perennial plants, growing to 10–80 cm tall, usu ...

'', but have been separated from that genus based on recent genetic and cytological data. Unlike the genus ''Arabis'' (x=8) ''Boechera'' has a base chromosome number of x=7. Many taxa are

triploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

. ''Boechera'' is a primarily North American genus, most diverse in the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, and its distribution range also includes

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

and the Russian Far East. The genus is poorly known, and species within are difficult to separate morphologically though some clearly distinct species are known. Most members of the genus are

perennial plant A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

s with pubescent leaves with stellate

trichomes Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

, narrow curving fruits, and small white to purple

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s in elongated

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s. Relationships within the genus are unclear, and some eastern North American species, including ''

Boechera laevigata ''Boechera laevigata'' is a species of flowering plant in the mustard family known by the common name smooth rockcress. It is native to many areas of the eastern United States and Canada, where it grows in calcareous rocky woods and bluffs. It is ...

'', may belong to a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

distinct from the rest of the genus. A very interesting feature of many species of the genus is

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the fu ...

, a process known as

apomixis In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal asexual reproduction" of plants, such as propagation from cuttin ...

Microsatellite A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...

data has revealed that some of the apomictic lineages are hybrids between two or more

sexual Sex is the biological distinction of an organism between male and female. Sex or SEX may also refer to: Biology and behaviour *Animal sexual behaviour **Copulation (zoology) **Human sexual activity **Non-penetrative sex, or sexual outercourse ** ...

parents.

Ecology

Species in this genus are one of the main food sources for the caterpillars of the butterfly ''

Pieris oleracea ''Pieris oleracea'', or more commonly known as the mustard white, is a butterfly in the family Pieridae native to a large part of Canada and the northeastern United States. The nearly all-white butterfly is often found in wooded areas or open pla ...

.''

Taxonomy

;Selected species *'' Boechera breweri'' (Brewer's rockcress) *'' Boechera canadensis'' (sicklepod) *'' Boechera cobrensis'' (sagebrush rockcress) *'' Boechera constancei'' (Constance's rockcress) *'' Boechera crandallii'' (Crandall's rockcress) *'' Boechera dentata'' (toothed rockcress) *'' Boechera depauperata'' (soldier rockcress) *'' Boechera dispar'' (pinyon rockcress) *'' Boechera falcatoria'' (Grouse Creek rockcress) *'' Boechera fecunda'' (sapphire rockcress) *'' Boechera gracilenta'' (Selby's rockcress) *'' Boechera gunnisoniana'' (Gunnison's rockcress) *''

Boechera hoffmannii ''Boechera hoffmannii'' (formerly ''Arabis hoffmannii'') is a rare species of flowering plant in the family Brassicaceae known by the common name Hoffmann's rockcress. It is Endemism, endemic to the Channel Islands of California, where it is know ...

'' (Hoffmann's rockcress) *'' Boechera holboellii'' (Holboell's rockcress) *''

'' (smooth rockcress) *'' Boechera lignifera'' (desert rockcress) *'' Boechera missouriensis'' (Missouri rockcress) *'' Boechera ophira'' (Ophir rockcress) *''

Boechera oxylobula ''Boechera oxylobula,'' common name Glenwood Springs rockcress, is a plant species referred to as ''Arabis demissa'' in many older publications. The species is endemic to Colorado. It is known only from Garfield, Gunnison, Hinsdale, Lake, Miner ...

'' (Glenwood Springs rockcress) *'' Boechera pallidifolia'' (Gunnison County rockcress) *'' Boechera patens'' (Spreading rockcress) *'' Boechera perennans'' (perennial rockcress) *'' Boechera perstellata'' (Braun's rockcress) *'' Boechera platysperma'' (pioneer rockcress) *'' Boechera pulchra'' (beautiful rockcress) *'' Boechera sparsiflora'' (sicklepod rockcress) *'' Boechera stricta'' (Drummond's rockcress) *'' Boechera tularensis'' (Tulare rockcress) *'' Boechera yorkii'' (Last Chance rockcress)

References

Brassicaceae genera {{Brassicales-stub