Surveys of local assemblages of plants and their pollinators are among the most useful ways to evaluate specialization in pollination and to discuss the patterns of plant-pollinator interactions among ecosystems. The high-altitude grasslands from southeastern Brazil constitute diminutive island-like formations surrounded by montane rainforests. We registered the floral traits of 124 species from the Serra da Bocaina grasslands (about 60% of the animal-pollinated species of this flora), and determined the pollinators of 106 of them. Asteraceae (40 species) and Melastomataceae (10 species) were prominent, while most families were represented by few species. The predominant floral traits were: dish or short-tubular shape; nectar as a reward; and greenish or violaceous colors. Pollinators were divided into eight functional groups (small bees, syrphids, other dipterans, etc.) and small bees, wasps, and large bees were the most important pollinators. Butterflies, beetles, and hummingbirds were poorly represented, and no bats, hawkmoths, or odor-collecting bees were detected. Plants were grouped in nine pollination systems, among which nectar-flowers pollinated by bees (28%), by wasps or wasps and flies (21%), or by several insect groups (19%) were the most representative. With regard to the degree of specialization, plant species were classified according to their number of pollinator groups. About 33% of the species were monophilous and 30% were oligophilous (i.e., pollinated by one or two functional groups, respectively). The remaining species were either polyphilous (17%) or holophilous (19%), a highly generalist system in which at least three groups act as indistinct pollinators. The general trends of the floral traits and plant-pollinator interactions at the Bocaina grasslands resemble those of biogeographic-connected ecosystems, such as the Venezuelan arbustal, and the Brazilian campo rupestre and cerrado. However, in the Bocaina grasslands, the mean number of pollinator types per plant was 2.09, one of the highest values obtained for worldwide floras. The origin of the high-altitude grasslands is linked to episodes of expansion and retraction due to glacial events. Such a situation may have favored species able to quickly occupy new habitats, including those that do not depend on a few highly specialized pollinators. The prevalence of Asteraceae may also be linked to more generalized pollination systems. Alternatively, some floral traits, such as spontaneous self-pollination and long-lived flowers, may be advantageous for species with more specialized systems in these grasslands with harsh climatic conditions and low rates of pollinator visitation.