Arabis canadensis L.
Family - Brassicaceae
Stems - To +50cm tall, herbaceous, from large taproot, simple to few-branched above, sparse hirsute to glabrous, erect.
Leaves - Alternate, sessile. Lower leaves oblanceolate to spatulate, to 10cm long, -3cm broad, with irregular shallow blunt teeth, obtuse to subacute. Upper leaves smaller than lower, lanceolate to lance-elliptic, acute, with few coarse irregular teeth, tapering to base. All leaves sparse hirsute, with ciliolate margins.
Lower and upper leaves respectively.
Inflorescence - Terminal raceme elongating in flower to +30cm long. Pedicels to 8mm long, hirsute(sparse), at right angles to axis at anthesis but quickly drooping.
Flowers - Petals 4, free, 3.6mm long, 1mm broad, white, glabrous, slightly exceeding sepals, linear. Stamens 6, not exceeding petals. Filaments white, 2.1mm long, glabrous. Anthers pale yellow. Ovary green, 2mm long, terete, glabrous. Sepals 4, distinct, green, 3mm long, 1.2mm broad, erect, hirsutulous. Siliques to 10cm long, +2mm broad, slightly compressed or flattened, curved(sub-falcate), distinctly nodding at maturity.
Sepals and pedicel.
Flowering - April - June.
Habitat - Open woods, dry slopes, open ground, rocky ledges.
Origin - Native to U.S.
Other info. - This is a tall, non-showy plant in flower, but is interesting in fruit. The long curved siliques hang down on the stem and are sure to catch the eye. The plant is actually native to this continent which is good considering all the other introduced members of this family growing in Missouri.
Photographs taken at the Parkville Nature Sanctuary, Platte County, MO., 5-5-00, and in Eminence, MO., 6-8-01.