Glandular Hairs and Secretory Ducts of Matricaria chamomilla (Asteraceae): Morphology and Histochemistry

The aim of the present work is to characterize the glandular hairs and the secretory ducts of Matricaria chamomilla (Asteraceae) morphologically, anatomically and histochemically. The glandular hairs are multicellular and biseriate with two basal cells, two peduncle cells and a secretory head composed of six cells. The histochemical tests show that the glands are positive for lipids, essential oils, sesquiterpene lactones, and pectic—like substances. The secretory ducts show a lumen surrounded by a layer of specialized cells, with the exception in the root where the ducts do not show any secretory epithelium. The histochemical tests show that the ducts are always positive for lipids, while the tests for the presence of essential oils and sesquiterpene lactones are heterogeneous in the plant organs considered.