Common Name: MUSTARD FAMILY
Habit: Annual to shrub; sap pungent, watery. Leaf: generally simple, alternate; generally both basal, cauline; stipules 0. Inflorescence: generally raceme, generally not bracted. Flower: bisexual, generally radial; sepals 4, generally free; petals (0)4, forming a cross, generally white or yellow to purple; stamens generally 6 (2 or 4), 4 long, 2 short (3 pairs of unequal length); ovary 1, superior, generally 2-chambered with septum connecting 2 parietal placentas; style 1, stigma entire or 2-lobed. Fruit: capsule, generally 2-valved, "silique" (length >= 3 × width) or "silicle" (length < 3 × width), dehiscent by 2 valves or indehiscent, cylindric or flat parallel or perpendicular to septum, segmented or not. Seed: 1--many, in 1 or 2 rows per chamber, winged or wingless; embryo strongly curved.
Genera In Family: +- 330 genera, 3780 species: worldwide, especially temperate. Note: Highest diversity in Mediterranean area, mountains of southwestern Asia, adjacent central Asia, western North America; some Brassica species are oil or vegetable crops; Arabidopsis thaliana used in experimental molecular biology; many species are ornamentals, weeds. Aurinia saxatilis (L.) Desvaux in cultivation only. Aubrieta occasional waif in central NCoR, Carrichtera annua (L.) DC. in SCo, Iberis sempervirens L., Iberis umbellata L. in PR, Teesdalia coronopifolia (Bergeret) Thell., Teesdalia nudicaulis (L.) W.T. Aiton in southern NCoRO, CCo. Cardaria, Coronopus moved to Lepidium; Caulostramina to Hesperidanthus; Guillenia to Caulanthus; Heterodraba to Athysanus; California taxa of Lesquerella to Physaria; Malcolmia africana to Strigosella.
eFlora Treatment Author: Ihsan A. Al-Shehbaz, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.

Common Name: ROCKCRESS
Habit: Perennial herb (biennial); caudex simple or branched, persistent leaf bases generally absent; rosetted or not; rosette at ground surface or elevated on woody base; hairs simple or 2--14-rayed, stalked or sessile. Stem: simple or branched, leafy. Leaf: basal petioled, simple, generally entire or dentate, generally hairy; cauline sessile, base generally lobed, entire or dentate. Inflorescence: generally elongated. Flower: sepals bases generally not sac-like; petals generally white, lavender, or purple, claw present or 0; pollen ellipsoid in sexual pls, spheric in plants with asexual seeds. Fruit: silique, dehiscent, generally linear, edges generally parallel, unsegmented, flat parallel to septum; stigma entire or 2-lobed. Seed: in 1 or 2 rows, winged or not.
Species In Genus: 110+ species: temperate North America, Russian Far East. Etymology: (T.W. Boecher, Danish cytogeneticist, 1909--1983) Note: Some species with both fertile & sterile stems. Previously included in Arabis, but the 2 genera in different tribes. Boechera horizontalis (Greene) Windham & Al-Shehbaz [Arabis suffrutescens S. Watson var. horizontalis (Greene) Rollins] not in California.
Unabridged Note: Hybrids with spheric pollen and morphological intermediacy generally more common than sexual diploids (with ellipsoid pollen).
eFlora Treatment Author: Michael D. Windham & Ihsan A. Al-Shehbaz
Reference: Windham & Al-Shehbaz 2006--2007 Harvard Pap Bot 11:61--88, 11:257--274, 12:235--257
Unabridged Reference: Al-Shehbaz 2003 Novon 13:381--391