Kuhlmanniodendron macrocarpum Groppo, Favaretto & Fiaschi (Lindackerieae, Achariaceae), a second species of the genus, is here described and illustrated. This species is known from a small number of collections from the state of Bahia, eastern Brazil, and considered endangered given its restricted geographical distribution and the rapid deforestation of the Brazilian Atlantic Rain Forest. Kuhlmanniodendron macrocarpum can be readily distinguished from K. apterocarpum, the other species of the genus, by its larger fruits (5–8 × 4–6 cm vs. 3–4 × 2.5–3 cm), the leaf venation pattern, and the disposition and number of stamens in male flowers. In addition to morphological characters used to characterize the new species, phylogenetic analyses were carried out using an rbcL sequence from the new species together with other Malpighiales sequences deposited in GenBank. These analyses involved maximum parsimony and Bayesian inference. The results confirmed the close relationship of the new species with K. apterocarpum in a strongly supported clade. Kuhlmanniodendron appeared close to Camptostylus, Lindackeria, Xylotheca, and Caloncoba in a strongly supported clade (posterior probability = 0.99) that corresponds with the tribe Lindackerieae of Achariaceae (Malpighiales). The arrangement of the stamens in the male flowers of the new species were investigated using transversal anatomical sections, revealing a combination of stamens with basally connate filaments externally arranged in a ring and internally arranged in sets of three (or two), the first report of this pattern of stamen arrangement in Achariaceae. Pollen of K. macrocarpum are 3-colporate and microreticulate, and typical of many eudicots. A picrosodic paper test was performed in herbarium dry leaves, and cyanogenic glycosides, a class of compounds usually found in Achariaceae, were detected. A detailed description and illustrations of this new species are provided, as well as comments on geographic distribution, phenology, generic relationships, and conservation status.