ABSTRACT Intraspecific floral variations may affect the degree of generalization and efficacy of pollinators, with consequences for plant reproductive success. Such effects could be greater for heterostylous plants because morphological variation can alter reciprocity between morphs. We evaluated the frequency, composition, and efficacy of pollinators, and the reciprocity (measured by population inaccuracy) of Psychotria nuda, a distylous species of Rubiaceae, in a montane forest. Moreover, we assessed the effects of corolla length on reciprocity and reproductive success. We recorded eighteen species of floral visitors, belonging to four functional groups. The frequency of visits differed among groups with butterflies being the most frequent visitors, in contrast to hummingbird-pollinated lowland populations. This difference did not affect reproductive success, since fruit set was similar between these populations. The total population inaccuracy was 21.56 mm2, with inaccuracy of low organs being higher (12.03 mm²) than that of high organs (9.53 mm²). Floral traits may have different effects on the reproductive success of morphs of distylous species; the corolla length of P. nuda only affected the reproductive success of short-styled flowers. Large corollas showed greater reproductive success and lower individual inaccuracies for this morph, indicating compensation for the effects of imperfect reciprocal herkogamy on reproductive success.

Orchidaceae is one of the largest and most diverse plant families in the world. The number of floristic studies of this family in Rio de Janeiro state, Brazil, has increased significantly in recent years. However, only a few such studies have been conducted in areas of restinga vegetation and none of those have examined the similarity, in terms of orchid diversity, among such areas. The present study sought to improve our knowledge of the Orchidaceae diversity occurring in Grumari restinga, as well to compare the diversity of orchids among Grumari and other restinga areas using cluster analysis. We found 15 genera and 19 species. Cluster analysis demonstrated that restingas located on islands are considerably different from those on the mainland, and no relationship was observed between floristic similarity and geographical proximity. As such, the present study shows that each area of restinga hosts different Orchidaceae species, demonstrating the importance of preserving this threatened ecosystem and this plant group.