ABSTRACT
The genus Phlomis is one of the largest genera in the Lamiaceae family and includes species used since ancient times in traditional medicine, as flavoring for food and as fragrance in cosmetics. The secretory structures (represented by glandular trichomes) as well as the essential oils produced by them constitute the subject of this review. While representatives of this genus are not typically regarded as large producers of essential oils compared to other species of the Lamiaceae family, the components identified in their essential oils and their biological properties necessitate more investigation of this genus. A comprehensive analysis of the specialized literature was conducted for each of the 93 currently accepted species to identify all the results obtained by researchers regarding the secretory structures and essential oils of this genus up to the present time. Glandular trichomes, still insufficiently studied, present morphological peculiarities that differentiate this genus within the family: they are of two categories: capitate (with a wide distribution in this genus) and dendroid. The peltate trichomes, characteristic of many species of this family, are absent. The essential oils from the species of the genus Phlomis have been much more widely studied than the secretory structures. They show considerable variability depending on the species and the environmental conditions.
ABSTRACT
Megastigmidae comprises more than 200 species in 12 genera. Megastigmus has a worldwide distribution with more than 150 species. Over 80% of these species are recorded from the Australian and Palearctic region, with a few from Afrotropical and Oriental regions, but none from the Neotropical region. We describe a new species of Megastigmus obtained from the seeds of Pemphis acidula in the Maldives Archipelago. This is the first mention of Megastigmidae having as a host plant a species from Lythraceae. It is also the first recorded association of Chalcidoidea with the genus Pemphis and the first mention of Megastigmidae and Megastigmus in the Maldives Archipelago. We provide a detailed description of the species, focusing on its morphology, using both light microscopy and scanning electron microscopy (SEM). Megastigmus irinae Popescu n. sp. is a strictly phytophagous species, with each larva consuming a single seed. Currently, M. irinae is an endemic species found only in the Maldives Archipelago. However, considering the distribution of its host plant, P. acidula, which ranges from East Africa to Southeast Asia, Australia, Micronesia, and French Polynesia, we anticipate that future research could significantly expand the known range of this interesting new species.
ABSTRACT
The purpose of this paper is to highlight the morphological peculiarities of glandular and non-glandular trichomes from leaves of Phlomis herba-venti subsp. Pungens using light, confocal, and scanning electron microscopy. Histochemistry techniques were used to analyze the localization of different chemical compounds in secretory trichomes. Two types of non-glandular trichomes were identified: unicellular and branched. They were found more frequently on the lower epidermis of leaves in different stages of ontogenetic development. Glandular trichomes were categorized as capitate (C1 and C2) with different stalk lengths and one-four secretory cells and dendroids (D) with one-four secretory cells. The histochemical analyses revealed distinct secretory products in terms of composition and distribution among the three types of glandular trichomes. The dendroid category of glandular trichomes is rarely found in plants and is not characteristic of the Lamiaceae species. They were described and characterized from a micromorphological and histochemical point of view for the first time in P. herba-venti.
