''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'', 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.''

Taxonomy

;Selected species *'' Boechera breweri'' (Brewer's rockcress) *'' Boechera cobrensis'' (sagebrush rockcress) *'' Boechera constancei'' (Constance's rockcress) *'' Boechera crandallii'' (Crandall's 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'' (Hoffmann's rockcress) *'' Boechera holboellii'' (Holboell's rockcress) *'' Boechera lignifera'' (desert rockcress) *'' Boechera ophira'' (Ophir rockcress) *'' Boechera oxylobula'' (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'' (Quebec rockcress) *'' Boechera sparsiflora'' (sicklepod rockcress) *'' Boechera stricta'' (Drummond's rockcress) *'' Boechera tularensis'' (Tulare rockcress) *'' Boechera yorkii'' (Last Chance rockcress)

References

Brassicaceae genera {{Brassicales-stub