Meniscium serratum Cav.

16.4. Meniscium serratum Cav., Descr. Pl. (Cavanilles) 548 (1803). Plants terrestrial. Stem short-creeping, glabrous. Fronds 97–110 cm long, monomorphic, pinnate; petiole 39–57.5 cm long, paleaceous to pale brown, angular, glabrous; rachis paleaceous, sulcate adaxially, with sparse acicular hairs on both sides; laminae 49–60 × 26.5–32 cm, lanceolate to oblong; pinnae median 14.5–18 × 3.2–3.7 cm, 8–11 pairs, oblong-lanceolate, chartaceous, abaxially with twisted acicular hairs on the costae and veins, rarely on the laminar tissue between the veins, adaxially glabrous, with sparse acicular hairs on the costae, margins serrate, base cuneate to rounded, apex acute to acuminate; veins anastomosed, 12–14 areoles between the costae and the margin of the pinnae. Sori not observed. Examined material: Barreiras do PiauÍ, Rio UruçuÍ Vermelho, 09°57’14’’S, 45°34’15’’W, 396 m, 20.IV.2022, P. H. C. Aguiar et al. 17 (CCAA). Meniscium serratum has wide Neotropical distribution, from Mexico to Argentina and in the Caribbean region (Fernandes & Salino 2020). In Brazil, it occurs in the Amazon, Cerrado, and Atlantic Rainforest biomes (Salino et al. 2023). In the present study, it is recorded as a new occurrence for the state of PiauÍ, having been observed in arenitic soil along the river banks. It is the only species of the genus in Brazil with pinnae with serrate margins. According to Fernandes & Salino (2020), Meniscium serratum resembles M. arborescens due to its generally ascendant and lanceolate pinnae, secondary veins forming a sigmoid pattern and twisted hairs abaxially on the costae veins and laminar tissue between the veins, whiles M. arborescens has undulate and crenate pinnate margins.