''Boechera'' (rockcress) 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 the family

Brassicaceae Brassicaceae () or (the older but equally valid) Cruciferae () is a medium-sized and economically important Family (biology), family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous pla ...

. It was named after the Danish botanist Tyge W. Böcher (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 *'' D ...

'' 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 organ ...

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

Arabidopsis thaliana ''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small plant from the mustard family (Brassicaceae), native to Eurasia and Africa. Commonly found along the shoulders of roads and in disturbed land, it is generally ...

''. 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 two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

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

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, and its distribution range also includes

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

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 In horticulture, the term perennial (''wikt:per-#Prefix, per-'' + ''wikt:-ennial#Suffix, -ennial'', "through the year") is used to differentiate a plant from shorter-lived annual plant, annuals and biennial plant, biennials. It has thus been d ...

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 Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s in elongated

raceme A raceme () or racemoid is an unbranched, indeterminate growth, 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 ...

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

Boechera laevigata ''Borodinia 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 i ...

'', may belong to a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

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 f ...

, a process known as

apomixis In botany, apomixis is asexual development of seed or embryo without fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils. Apomictically produced offspring are geneti ...

Microsatellite A microsatellite is a tract of repetitive DNA in which certain Sequence motif, 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 organ ...

data has revealed that some of the apomictic lineages are hybrids between two or more sexual 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 ''Boechera'' (rockcress) is a genus of the family Brassicaceae. It was named after the Danish botanist Tyge W. Böcher (1909–1983), who was known for his research in alpine plants, including the mustards ''Draba'' and ''Boechera holboellii''. ...

'' (Brewer's rockcress) *''

Boechera cobrensis ''Boechera cobrensis'' ( syn. ''Arabis cobrensis'') is a species of flowering plant in the mustard family known by the common names Masonic rockcress and sagebrush rockcress. It is native to the western United States from eastern California to Wy ...

'' (sagebrush rockcress) *''

Boechera constancei ''Boechera constancei'' is a species of flowering plant in the mustard family known by the common name Constance's rockcress. It is endemic to California, where it is known only from the northern Sierra Nevada of Plumas and Sierra Counties. It ...

'' (Constance's rockcress) *''

Boechera crandallii ''Boechera crandallii'', or Crandall's rockcress, is found in Wyoming and Colorado where it is found on limestone chip-rock and stony areas, often among sagebrush. Flowering time is from May to June. According to chromosome counts by Rollins (19 ...

'' (Crandall's rockcress) *''

Boechera depauperata ''Boechera'' (rockcress) is a genus of the family Brassicaceae. It was named after the Danish botanist Tyge W. Böcher (1909–1983), who was known for his research in alpine plants, including the mustards ''Draba'' and ''Boechera holboellii''. ...

'' (soldier rockcress) *''

Boechera dispar ''Boechera dispar'' is a species of flowering plant in the family Brassicaceae known by the common name pinyon rockcress. It is native to eastern California and western Nevada, where it grows in rocky areas in desert and mountain habitat. This is ...

'' (pinyon rockcress) *''

Boechera falcatoria ''Boechera falcatoria'' (formerly ''Arabis falcatoria'') is a rare species of flowering plant in the family Brassicaceae known by the common name Grouse Creek rockcress. It is endemic to Utah in the United States, where it is known only from Box ...

'' (Grouse Creek rockcress) *'' Boechera fecunda'' (sapphire rockcress) *'' Boechera gracilenta'' (Selby's rockcress) *'' Boechera gunnisoniana'' (Gunnison's rockcress) *'' Boechera hoffmannii'' (Hoffmann's rockcress) *''

Boechera holboellii ''Boechera holboellii'', or Holbøll's rockcress, is a species of plant in the family Brassicaceae. Its cytology has been much studied by the Danish botanist Tyge W. Böcher. Circumscription of this species has varied, with earlier works treati ...

'' (Holboell's rockcress) *'' Boechera lignifera'' (desert rockcress) *'' Boechera ophira'' (Ophir rockcress) *''

Boechera oxylobula ''Boechera'' (rockcress) is a genus of the family Brassicaceae. It was named after the Danish botanist Tyge W. Böcher (1909–1983), who was known for his research in alpine plants, including the mustards ''Draba'' and ''Boechera holboellii''. ...

'' (Glenwood Springs rockcress) *'' Boechera pallidifolia'' (Gunnison County rockcress) *'' Boechera patens'' (Spreading rockcress) *'' Boechera perennans'' (perennial rockcress) *'' Boechera platysperma'' (pioneer rockcress) *'' Boechera pulchra'' (beautiful rockcress) *''

Boechera quebecensis ''Boechera quebecensis'', commonly known as the Quebec rockcress, is a critically imperiled herbaceous plant, herbaceous biennial plant, biennial or short-lived perennial plant, perennial flowering plant in the Brassicaceae family. It is endemism ...

'' (Quebec rockcress) *''

Boechera sparsiflora ''Boechera sparsiflora'' (formerly ''Arabis sparsiflora'') is a species of rockcress known by the common names sicklepod rockcress and elegant rockcress. It is native to western North America from California to Utah to Yukon, where it can be fou ...

'' (sicklepod rockcress) *''

Boechera stricta ''Boechera stricta'' (Synonym (taxonomy), syn. ''Arabis drummondii'', ''Boechera drummondii'', ''Turritis stricta'') is a species of flowering plant in the Brassicaceae, mustard family known by the common name Drummond's rockcress. It is native t ...

'' (Drummond's rockcress) *'' Boechera tularensis'' (Tulare rockcress) *'' Boechera yorkii'' (Last Chance rockcress)

References

Brassicaceae genera {{Brassicales-stub