Pteropsiella metzgeriiformis Spruce ex Steph.

Fernandes, Rozijane Santos, Silva, José Augusto dos Santos, Ottoni, Felipe Polivanov & Pinheiro Costa, Denise, 2021, Diversity of thalloid liverworts in Brazilian Savanna of Parque Nacional da Chapada das Mesas, Maranhão, Brazil, Check List 17 (1), pp. 45-58 : 50

Pteropsiella metzgeriiformis Spruce ex Steph.

Figure 4A–D

Material examined. BRAZIL – Maranhão • Carolina, ParqueNacionalChapadadasMesas, RiachoCorrente ; 07° 04′25″S, 047°05′26″W; alt. 277 m; 07 Jun. 2018; J. A. S Silva 294 col.; CCAA 1558 .

Identification. Plants terrestrial. Thallus light green, 10–30 × 0.3–0.5 mm; branches inserted ventrally; midrib rounded in cross-section, with six cortical cells (two dorsal and four ventral, and less than 15 medullary cells); wings narrow and unistratose; dorsal surface of thallus without pores and air chambers; ventral surface with chlorophyllose cells; margin toothed, green, with one or two sausage-shaped papillae; scales absent. Sporophyte arising from leafy branches.

Pteropsiella is sometimes misidentified as species of Metzgeriaceae because they also have a unistratose, flat thallus, with a midrib. However, Pteropsiella has a toothed, green margin with one or two sausage-shaped papillae, and rhizoids present only on the midrib, while Metzgeriaceae has thallus margins with rhizoids and gametoecia on the ventral side of the midrib. Pteropsiella

metzgeriiformis differs from P. frondiformis by the light green thallus with fewer than 15 medullary cells, while P. frondiformis has a dark green thallus with more than 15 medullary cells.

Distribution and ecology. Brazil and Colombia (Lisboa 1976; Gradstein and Costa 2003; Pinzón et al. 2003; Carmo and Peralta 2016; Costa et al. 2017). Brazilian biomes and states: Amazonia (Amazonas and Roraima) and Atlantic Forest (Minas Gerais) ( Carmo and Peralta 2016; Costa et al. 2017); and Brazilian Cerrado (Maranhão; new data). We collected this species near an open, sunny, sandy stream bank.

Monocleaceae