Revisão taxonômica de Phyllanthus subsect. Clausseniani G.L. Webster (Phyllanthaceae)

Abstract

Phyllanthus has about 880 species, divided into 18 subgenera, 70 sections and 14 subsections, therefore, it is considered the largest and most diversified genus of Phyllanthaceae. Among the sections, Phyllanthus sect. Phyllanthus for being the largest comprising 45 species included in four subsections [Almadenses, Clausseniani, Niruri and Pentaphylli]. Phyllanthus subsect. Clausseniani is referred to as exclusive to Brazil and until then, it was represented by 17 species, recognized by the peculiar morphology of its deeply emarginated anthers or with distinct and often spipitated teak, in addition to the 4-colporate pollen grains. Considering the morphological complexity, the imprecise interspecific limits and the nomenclatural and typification problems, this thesis aimed to review the morphological characters of the species of P. sect. Phyllanthus subsect. Clausseniani in order to update his taxonomy. For this purpose, approximately 545 specimens from 57 national and international herbaria were analyzed, as well as material from expeditions carried out in different Brazilian regions. The results were organized into seven manuscripts, of which three were published, three are accepted and one will be submitted for publication. (1) In the first manuscript, six typifications were carried out, and a new synonymization, so that Phyllanthus atalaiensis becomes synonymous with P. heteradenius. (2) In the second manuscript, we suggest the conservation of the name Phyllanthus claussenii on P. udicola. (3) In the third manuscript, we bring to light the rediscovery of new Phyllanthus itatiaiensis individuals in the state of Rio de Janeiro after 50 years, as well as the expansion of its distribution to the state of Minas Gerais. (4) In the fourth manuscript, we update the geographic distribution and present new records of Phyllanthus allemii, a rare species from the Brazilian Cerrado. (5) In the fifth manuscript, we describe the new endemic species from Northeastern Brazil, Phyllanthus dardanoi. (6) In the sixth manuscript, we propose two new species endemic to the Brazilian Atlantic Forest, specifically from the Southeast region of Brazil. (7) The seventh manuscript deals with the review by P. sect. Phyllanthus subsect. Clausseniani. In this manuscript, we suggest expanding the circumscription of the subsection from 17 to 27 species and updating its morphological concept. Additionally, we describe five new species (P. draconicaudus, P. hialinum, P. pedrosae, P. rupiculum e P. serranum), we chose two new synonyms for P. subemarginatus, as well as we proceeded with the lectotyping of P. blanchetianus and P. lagoensis. However, this work also brings complete descriptions, distribution maps, as well as records of new occurrences for some Brazilian states, as well as comments on ecology, phenology, conservation and taxonomic comments for species recognition. An identification key is added, along with previously unpublished illustrations and in situ photos, making identification more objective and accurate. Even so, pollen morphology, seed morphology and leaf blade clarification were useful to distinguish some species and also to characterize the subsection, even though they were not so informative for the distinction of many species.