According to the investigations of J.Gadamer2), the so-called American or perennial winter-cress, Barbaraea praecox, R. Br. contains the glucoside gluconasturtiin, also found in Nasturtium officinale, L. (Ger. Brunnenkresse). Upon distillation both plants yield identical oils, consisting principally of phenyl ethyl mustard oil (m.p. of thiourea 135 to 136°).