Arabis laevigata (Muhl. ex Willd.) Poir.
Habitat: Rich woods and slopes or shaded ledges. [Rocky summits and outcrops (non-forested, upland); Hardwood to mixed forest (forest, upland)]
Range: Southwest Quebec to Colorado, south to Georgia and west to Oklahoma.
Aids to Identification: Smooth rockcress grows to 1 m in height with pods 8-10 cm long spreading horizontally. The flowers are greenish white or white, 0.5 cm or less wide. The glaucous stem and clasping, auricled leaves differentiate it from similar species.
Ecological characteristics: Known to occur in Maine on xeric to moist circumneutral cliff faces, ledges and talus slopes.
Phenology: Flowers April - June.
Synonyms: Known as Boechera laevigata (Muhl. ex Willd.) Al-Shehbaz and formerly Turritis laevigata Muhl. ex Willd.
Known Distribution in Maine: This rare plant has been documented from a total of 6 town(s) in the following county(ies): Aroostook, Franklin, Oxford, Piscataquis, York.
Dates of documented observations are: 1896, 1984, 1990 (2), 1993, 2000
Reason(s) for rarity: Near edge of range; habitat is naturally scarce.
Conservation considerations: These plants typically grow on ledges in forested areas; the effects of logging in the surrounding woods is unknown. Partial removal of the canopy could mimic natural conditions since ledge habitats are frequently semi-open themselves.