سیده باهره جوادی - Researcher, Department of Botany, Iranian Research Institute of Plant Protection, P.O. Box ۱۴۵۴, Tehran ۱۹۳۹۵, Iran (E-mail: sb_djavadi@hotmail.com)

In the identification process of weed materials available in "IRAN" herbarium, a specimen belonging to the genus Lactuca (Asteraceae) had the following characteristics: Plant annual, many stemmed from base; stem erect-slightly procumbent, slender, glabrous, whitish and leafy. Basal leaves dried; stem leaves ca. ۷ × ۰.۵ cm, glabrous, linear-lanceolate, entire at margin, sessile, auriculate, auricles small, forming a hastate leaf base. Inflorescence spike-like; heads in the axils of reduced leaves, shortly pedicelate, solitary or in clusters of ۲-۳; involucres narrow, ca. ۱۲ mm long; florets turning purplish when dry. Achenes ca. ۴ × ۱ mm, light brown, flattened, inversely ovate, many-ribbed, in upper part provided with short hairs, with filiform ۳-۳.۵ mm long beak; pappus white, deciduous.