Distribuição, riqueza e similaridade de Passovia e Psittacanthus (Loranthaceae) no Amazonas, BR

Abstract

Loranthaceae are hemiparasitic plants, commonly known as mistletoes, comprising 12 genera and approximately 130 species occurring in Brazil, out of a total of 800 species found in tropical and subtropical regions around the world. In the Amazon, Psittacanthus and Passovia are highly diverse genera; however, few studies have focused on their distribution. Nevertheless, taxonomic studies, floristic inventories, and phenological research are important sources of information for understanding species in a given area. Thus, the objective of this study was to present the distribution, diversity, and geographic similarity of these two Loranthaceae genera (Passovia and Psittacanthus) in the state of Amazonas, as well as to compile information on flowering and fruiting phenology based on herbarium data. To achieve this, a bibliographic review was conducted along with consultation of available virtual herbaria. Twelve species of Passovia were found to be present in 28 municipalities, and 21 species of Psittacanthus were found in 37 municipalities (out of the 62 in the state). Passovia pycnostachya was reported to occur in the state of Amazonas in a review article; however, no records of it were found in any other source used in this study, nor were any specimens deposited in herbaria. On the other hand, Psittacanthus dentatus, Passovia bisexualis, and Passovia stenophylla were not cited in the literature, yet there are herbarium specimens available. Psittacanthus cucullaris was the only species with sufficient information to infer its flowering phenology, which occurs between January and September, and fruiting between March and August, with April being the peak month for both flowers and fruits. Regarding geographic similarity, both genera showed a gradual staircase-like dissimilarity, representing a similarity gradient. However, these results do not reflect the actual similarity patterns for these genera due to the lack of data in nearly all the studied municipalities. Nevertheless, compiling and organizing this data may serve as a valuable resource for future studies and synthesizes the current knowledge of this under-researched plant group in the state.