Anatomical features of ecological importance and taxonomic value revealed by scanning electron microscopy and light microscopy in Camonea umbellata (L.) A.R. Simões & Staples (Convolvulaceae).

This article describes detailed and novel data on the anatomy and histochemistry of leaves, stems, and roots of Camonea umbellata (L.) A.R.Simões & Staples in different environments for the identification of characters with taxonomical value and of ecological importance, with provision of light and scanning electron microscopy images. To analyze the characters, we collected samples of the vegetative organs of three individuals in each of three populations, which were in a grazing area, an urban environment, and a biological reserve. The main diagnostic anatomical markers for the identification of C. umbellata include amphistomatic leaves, tetracytic and brachyparatetracytic stomata, peltate trichomes, long simple trichomes, epidermis with striated cuticle ornamentation, mesophyll with acute borders, presence of druses, secretory channels, angular collenchyma, fibrous pericycle in the stem, intraxylary phloem in the vegetative organs, oil bodies throughout the midrib, petiole, stem and root, and epicuticular waxes of the crust and coiled rodlet types. Since the characters above did not show variation in the environments evaluated, we consider these characters taxonomically useful for the identification of C. umbellata. RESEARCH HIGHLIGHTS: The anatomy of the aerial vegetative organs of Camonnea umbellata retains common Convolvulaceae characters. The sinuosity of the epidermal cell walls and the density of trichomes in the epidermis of the petiole were visually variable characters among the analyzed individuals. Amphistomatic leaves, tetracytic and brachyparatetracytic stomata, peltate trichomes, epidermis with striated cuticle ornamentation, dorsiventral mesophyll with border acute, presence of druses, secretory structures, angular collenchyma, fibrous pericycle in the stem, intraxillary phloem, presence of oil bodies in all organs, and epicuticular waxes of the crust type and coiled rods were considered important anatomical markers for the recognition and correct identification of Camonea umbellata.

Leaf and stem micromorphology of Jacquemontia evolvuloides (Moric.) Meisn. (Convolvulaceae) populations: New insights for taxonomic classification using light and scanning electron microscopy.

Morphoanatomical studies can provide useful and relevant information to support taxonomic groupings. Jacquemontia evolvuloides shows great morphological variability, which has led to numerous taxonomic classifications. To determine if anatomical characters can be used to recognize operational taxonomic units within populations of that species, we analyzed the leaves and stems of 22 populations using light and scanning electron microscopy. The variability of the analyzed characters allowed the grouping of these populations into five morphotypes. The presence of paracytic stomata, laticiferous canals, and stellate trichomes can be considered diagnostic characters of J. evolvuloides. The presence and types of epicuticular waxes, as well as a layer similar to palisade parenchyma in the petioles and stems, the classifications of glandular trichomes, and new types of stomata (anomocytic, anomotetracytic, and brachyparatetracytic) are reported here for the first time for Jacquemontia. The results discussed here help clarify the classification of this species complex and contribute to the taxonomy of Jacquemontia-a genus that has historically been difficult to define due to its wide morphological variation at the species level. RESEARCH HIGHLIGHTS: Seven types of epicuticular waxes were identified among J. evolvuloides specimens: granules, threads, entire platelets, coiled rodlets, fissured layers, membranous platelets, and tubules. Six types of trichomes were observed among J. evolvuloides populations: stellate, malpighiaceous, sessile peltate glandular, short pedunculate glandular, stipitate-glandular, and capitate glandular. We observed that six populations of Jacquemontia evolvuloides located in the Brazilian Caatinga domain have unprecedented sessile peltate trichomes restricted to the main leaf midrib, which were only observed under light microscopy.