BOECHERA Á. Löve & D. Löve, Bot. Not. 128: 513. 1975.
Ihsan A. Al-Shehbaz and Michael D. Windham
Tribe: Boechereae Al-Shehbaz, Beilstein & E.A. Kellogg, Pl. Syst. Evol. 259: 111. 2006.
Name derivation: after Tyge Wittrock Böcher, 1909–1983, a Danish cytogenetist who worked on subarctic flowering plants
Type species: Boechera holboellii (Hornemann) Á. Löve & D. Löve (based on Arabis holboellii Hornemann.
Herbs, sexual or apomictic, perennial or rarely biennial; caudex (when present) simple or branched. Trichomes simple or branched and stalked or sessile, 2–14-rayed, sometimes dendritic, not stellate. Stems simple or branched apically. Basal leaves petiolate, rosulate or not, simple, entire or dentate, rarely lyrate-pinnatifid; cauline leaves sessile or very rarely short petiolate, sometimes auriculate or sagittate, entire or dentate. Inflorescences ebracteate, sometimes in panicles, often elongated in fruit; fruiting pedicels erect, ascending, or divaricate, or reflexed, secund or not. Sepals ovate or oblong, base of lateral pair slightly saccate or not, margin membranous; petals white, pink, or purple; blade spatulate or oblanceolate, apex obtuse; claw shorter than sepals or undifferentiated from blade; stamens 6, tetradynamous; filaments not dilated at base; anthers ovate or oblong, obtuse at apex; pollen ellipsoid (sexual plants) or spheroid (apomictic); nectar glands confluent, subtending bases of all stamens; lateral glands semi-annular or annular; ovules and seeds 8–216 per fruit. Fruits dehiscent siliques, linear, rarely oblong or lanceolate, straight or falcate, variously oriented, latiseptate, sessile or rarely shortly stipitate, glabrous or rarely pubescent; valves papery, with an obscure or prominent midvein, smooth or torulose; replum rounded, visible; septum complete, membranous, veinless; style obsolete or distinct; stigma capitate, entire. Seeds uniseriate or rarely biseriate in each locule, winged, margined, or wingless, oblong or orbicular, flattened; seed coat smooth or minutely reticulate, rarely papillate, not mucilaginous when wetted; cotyledons accumbent.
About 110 species: United States, Canada, n Mexico; Russian Far East.
References: Al-Shehbaz (2003d, 2005c), Windham & Al-Shehbaz (2006, 2007a, 2007b).
A very complex genus and for detailed discussion of such complexity and taxonomic notes, as well as the piutative parental species of the triploids, see the references above.
interactive key to the species is being prepared