Resumo Apresentamos o tratamento florístico de Acanthaceae na Serra Negra, região pertencente à Serra da Mantiqueira. Registramos nove gêneros e 16 espécies de Acanthaceae: Aphelandra longiflora, Hygrophila costata, Hypoestes phyllostachya, Justicia carnea, J. dasyclados, J. minensis, J. serrana e J. citrina, Lepidagathis kameyamana, Mendoncia puberula, M. velloziana, Odontonema barleriodes, Ruellia brevifolia, R. elegans, R. macrantha e Staurogyne euryphylla. Ocorrem naturalmente na Mata Atlântica e em outros domínios brasileiros, encontradas predominantemente em ambientes florestais. Espécies estudadas tiveram sua área de distribuição ampliada, com novos registros para a Mata Atlântica e para o estado de Minas Gerais. São apresentadas descrições morfológicas das espécies, chave de identificação, fotografias e dados sobre distribuição geográfica.

Abstract We provide the floristic treatment for Acanthaceae in the Serra Negra, a region belonging to the Mantiqueira Range. We recorded nine genera and 16 species of Acanthaceae: Aphelandra longiflora, Hygrophila costata, Hypoestes phyllostachya, Justicia carnea, J. citrina, J. dasyclados, J. minensis, J. serrana, Lepidagathis kameyamana, Mendoncia puberula, M. velloziana, Odontonema barleriodes, Ruellia brevifolia, R. elegans, R. macrantha, and Staurogyne euryphylla. They occur naturally in the Atlantic Rainforest and other Brazilian domains, found predominantly in forest environments. Species studied had their distribution area expanded, with new records for the Atlantic Rainforest and for the state of Minas Gerais. Morphological descriptions, identification key, photographs, and the geographic distribution are provided for each species.

Abstract The influence of Guarea guidonia (L.) Sleumer diaspore abundance on ants’ preference was studied in a secondary tropical forest area in Brazil. We offered seeds in stations with different abundances (one, two, five or 10 diaspores) for interactions with ants. The number of interactions and of ants were influenced by diaspore abundance during the observation period. Stations with 10 diaspores maintained a high number of interactions throughout the experiment. Incidence of seed cleaning differed among the four groups. Moreover, the number of interactions was positively related to the average percent of seeds cleaned. Diaspore abundance proved to be important for promoting more interactions with ants. Considering that the proportion of seeds cleaned increased with the number of interactions, further experiments should observe ant activity for a longer period. Furthermore, diaspore abundance should be considered in future studies of interactions with ants.

ABSTRACT Ants interact with seeds, and frequently remove their appendages. This work aimed to evaluate the effect of ants on the germination of Guarea guidonia (Meliaceae) seeds through removing the fleshy tissue of their integument (sarcotesta). The seeds were subjected to the following treatments: control (no sarcotesta removal), manual removal, and removal by ants. The results show that germination percentage and time varied among treatments, with removal by ants showing the highest percentage within the shortest possible time. The positive effect of sarcotesta removal by ants points to a possible action of anti-fungal substances. As germination is an essential step for recruitment, ant activity may be important to the regeneration of a deforested area. Further studies should consider germination experiments under natural conditions in order to increase the understanding on plant development.

RESUMO Este trabalho consiste do tratamento taxonômico das Acanthaceae Juss. na Marambaia, Estado do Rio de Janeiro, e sua distribuição nas diferentes formações vegetais locais. Foram constatados cinco gêneros e nove espécies encontradas nos manguezais, na restinga e na floresta ombrófila, além de áreas urbanizadas. Thunbergia alata é introduzida e amplamente naturalizada no Brasil inteiro e Ruellia blechum é uma espécie neotropical também naturalizada; as demais espécies (Avicennia schaueriana, Aphelandra longiflora, Justicia brasiliana, J. cydoniifolia, J. plumbaginifolia, Ruellia solitaria e Schaueria litoralis) são nativas. São apresentadas chave de identificação, descrições, ilustrações, comentários taxonômicos e a ocorrência nas formações vegetais locais, em outras restingas fluminenses e no Brasil. As espécies de Acanthaceae da Marambaia são recursos importantes para diferentes grupos de polinizadores e reúnem espécies típicas (Justicia brasiliana, J. cydoniifolia) e exclusivas (Schaueria litoralis) das restingas; essas espécies, juntamente com Avicennia schaueriana, são ameaçadas de extinção na flora fluminense.

ABSTRACT This work consists of the taxonomic treatment of the Acanthaceae Juss. in Marambaia, State of Rio de Janeiro, Brazil, and their distribution in the different local plant communities. Five genera and nine species were found in mangrove, sand coastal plains (restingas), rain forest, and in urban areas. Thunbergia alata is introduced and widely naturalized throughout Brazil, and Ruellia blechum is a neotropical species also naturalized; the other species are native: Avicennia schaueriana, Aphelandra longiflora, Justicia brasiliana, J. cydoniifolia, J. plumbaginifolia, Ruellia solitaria, and Schaueria litoralis. Keys to species, descriptions, illustrations, comments on taxonomy, and their distribution in the local plant communities, in other restingas in Rio de Janeiro State, and in Brazil are provided. The species of Acanthaceae in Marambaia are important resources for different groups of pollinators and include typical (Justicia brasiliana, J. cydoniifolia) and exclusive (Schaueria litoralis) species of the restinga; these species plus Avicennia schaueriana are threatened in Rio de Janeiro State.