The leaves and ramicaules of 16 epiphytic species from the genera Acianthera, Anathallis, and Specklinia belonging to the subtribe Pleurothallidinae were analyzed anatomically in order to find useful traits for the distinction of genera and species. The present study reveals that the leaves of Pleurothallidinae species possess anatomical characteristics such as trichomes, vascular bundles, and idioblasts, which are valuable for distinguishing such genera. We also found that leaf characteristics, such as the shape of epidermal cells, margin type, cuticle ornamentation, hypodermis, and presence of idioblasts, in conjunction with characteristics of the ramicaule, such as cross-section shape and cell type of the external cortex, can be used to distinguish species. A key to the genera based on data is provided and some characteristics are discussed regarding epiphytism.