Propolis, a honeybee product, has gained popularity as a food and alternative medicine. Its constituents have been shown to exert pharmacological effects, such as anti‐microbial, anti‐inflammatory and anticancer. Shoot apices of Baccharis dracunculifolia (alecrim plant, Asteraceae) have been pointed out as sources of resin for green propolis. The present work aimed (i) to observe the collecting behavior of bees, (ii) to test the efficacy of histological analysis in studies of propolis botanical origin and (iii) to compare the chemistries of alecrim apices, resin masses and green propolis. Bee behavior was observed, and resin and propolis were microscopically analyzed by inclusion in methacrylate. Ethanol extracts of shoot apices, resin and propolis were analyzed by gas chromatography/mass spectroscopy. Bees cut small fragments from alecrim apices, manipulate and place the resulting mass in the corbiculae. Fragments were detected in propolis and identified as alecrim vestiges by detection of alecrim structures. Prenylated and non‐prenylated phenylpropanoids, terpenoids and compounds from other classes were identified. Compounds so far unreported for propolis were identified, including anthracene derivatives. Some compounds were found in propolis and resin mass, but not in shoot apices. Differences were detected between male and female apices and, among apices, resin and propolis. Alecrim apices are resin sources for green propolis. Chemical composition of alecrim apices seems to vary independently of season and phenology. Probably, green propolis composition is more complex and unpredictable than previously assumed.

Colleters are secretory structures that occur in vegetative or reproductive shoot apices of many botanical families. However, in the order Myrtales, reports of colleters have considered only external morphology. We therefore evaluated apical meristems of 52 species belonging to 17 genera from seven tribes of subfamily Myrtoideae (Myrtaceae), so as to analyse the incidence and morphological types of colleters. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on fresh and methacrylate-embedded material. Proteins of the colleter secretions were analysed by SDS-PAGE. We have classified and described the following three new colleter types: petaloid, conic and euryform. None of the species contained all three colleter types. The petaloid colleters were present in three tribes (Syzygieae, Melaleuceae and Lophostemoneae). The conic colleters were observed in three tribes (Leptospermeae, Myrteae and Melaleuceae) and the euryform type occurred in five tribes (Leptospermeae, Syncarpieae, Myrteae, Syzygieae and Melaleuceae). In the tribe Eucalypteae, we found no evidence of colleters. The presence of mucilaginous secretion that defines colleters was confirmed by histochemical tests, and no proteins were found in the secretion. The colleters in Myrtoideae may help clarify the phylogenetic relationships of the Myrtaceae family.

The occurrence of nonarticulated laticifers has been recorded in the literature for Apocynaceae, but little information is available on their structure and the chemical compounds in their latex. The objective of this study was to describe, anatomically and histochemically, the laticifers and latex found in the roots, stems, and leaves of Mandevilla atroviolacea (Stadelm) Woodson, a genus in the Apocynaceae. Laticifer anatomy was examined by light microscopy, and the chemical nature of the exuded latex was studied using cytochemistry. Articulated laticifers were present in M. atroviolacea. The lactiferous system in stems and leaves originated from both procambium and ground meristem, and it was determined to be functional, as indicated by changes in the cytoplasm immediately subsequent to its formation. However, in tuberous roots, laticifers originated from the vascular cambium, phellogen, and parenchymatous cortical cells. The primary wall of laticifers consists of pectins and cellulose and is thicker than that of adjacent cells. The laticifer secretion contained an emulsion of lipophilic substances rich in neutral lipids, resin oils, and possibly rubber. The presence of articulated laticifers is reported for the first time for Apocynoideae, contributing to the knowledge and understanding of these structures in the family Apocynaceae.