The Pterogyne nitens Tul., popularly known as "amendoim-bravo," belongs to the Fabaceae family and can be used in the recovery of degraded areas and in the restoration of riparian forests. The objective of this study was to biometrically characterize the seeds of "amendoim-bravo" and study the influence of substrates on the physiological potential of the seeds. For biometric characterization, eight replicates of 100 seeds were used to determine length and width. In the germination test using a completely randomized experimental design, the seeds were distributed in five different substrates: paper towel in roll form, between blotting paper, on top of blotting paper, between sand, and commercial substrate, at a regulated temperature of 30°C in a Biochemical Oxygen Demand (B.O.D) chamber. The first germination count (PCG), germination speed index (IVG), root length, shoot length of seedlings, dry root mass, and shoot mass of seedlings were analyzed. Evaluating the first germination count and germination index, the paper towel roll substrate showed superiority with 96% and 98%, respectively, statistically differing from the other treatments. The value for germination speed index also highlighted the use of the paper towel roll (6.347). Regarding mean time, mean speed, and synchrony, the best results were also achieved with the paper towel roll substrate. Pterogyne nitens Tul. seeds have an average length of 11.52 mm and a width of 6.35 mm. For evaluating physiological potential, the use of the paper towel roll substrate is recommended.