ABSTRACT Croton section Adenophylli is the largest section in the genus, with around 223 species distributed in the neotropical region. One of the main diagnostic characteristics of this section is the fruit columella, which has three prominent ascending terminal appendages. During a taxonomic review of this section in Brazil, we observed that C. campestris has a problematic taxonomic circumscription, thereby being confused with some other congeners. We investigate the circumscription of C. campestris through the examination of several herbarium specimens across its entire geographic range, and in its different habitats. We conducted macro- and micro-morphological studies as well as molecular analyses based on DNA sequences. Our results allow us to propose two new species (C. hatschbachii and C. stellatorotatus), update the nomenclature of C. campestris and C. subvillosus, and define the systematic positions, phylogenetic relationships, morphology and leaf anatomy of the above-mentioned taxa. The species are described, and their geographic distributions, morphological relationships, flowering and fruiting times, and conservation statuses are commented on. The two new species are also illustrated. Seventeen new synonyms, thirteen lectotypes and two neotypes are proposed. We also provide a key for the identification of 11 taxa belonging to the section Adenophylli, previously confused with C. campestris.

Resumo Estudos sobre a família Orchidaceae no Parque Nacional da Chapada dos Veadeiros, revelou uma nova ocorrência para a flora do estado de Goiás. Bulbophyllum adiamantinum até então considerada endêmica do estado de Minas Gerais, é aqui descrita, ilustrada, comentada quanto a sua distribuição, relações morfológicas e épocas de floração e frutificação. Adicionalmente, são fornecidos um mapa com a distribuição da espécie, seu status de conservação, além de imagens e notas sobre a anatomia de seu sistema vegetativo e de B. insectiferum, com a qual pode ser confundida. Anatomicamente, ambas as espécies se diferenciam principalmente pela presença ou ausência de corpos silicosos no sistema vegetativo, de idioblastos traqueoidais no mesofilo, pelo arranjo das fibras e aspecto do lume nas células da exoderme, endoderme, periciclo e medula nas raízes. Os caracteres que mostraram-se variáveis foram o número de feixes vasculares, o formato das células da epiderme e a espessura da cutícula das espécies estudadas.

Abstract Studies on the Orchidaceae family in the Chapada dos Veadeiros National Park revealed a new occurrence for the family to the flora of the Goiás state. Bulbophyllum adiamantinum, hitherto considered endemic to the state of Minas Gerais, is described here, illustrated, commented on its distribution, morphological relationships and period of flowering and fruiting. In addition, a map with distribution this species, its preliminary conservation status, images and notes on the anatomy of its vegetative system and its more morphologically, B. insectiferum, with which it can be confused, are provided. Anatomically, both species differ mainly by the presence or absence of silica bodies in the vegetative system and tracheoid idioblasts in the mesophyll, by the arrangement of the fibers and the appearance of the lumen of the cells of the exoderm, endoderm, pericycle and medulla in the roots. The characters that showed themselves to be variables were the number of vascular bundles, the shape of the cells of the epidermis and the thickness of the cuticle of the species studied.