Marchantia Linnaeus (1753: 1137) subg. Preissia Corda (1829: 647) D.G.Long, Crandall-Stotler, L.L.Forrest & Villarreal, comb. et stat. nov. Basionym:— Preissia Corda (1829: 647) in Opiz (ed.), Type:— Marchantia quadrata Scopoli (1772: 355). Marchantia subg. Preissia differs from the other three subgenera of Marchantia in lacking gemma-cups and gemmae on the thalli, bearing only two rows of ventral scales, and having the antheridiophore disc unlobed, archegoniophore with shortly lobed receptacle, and archegoniophore stalk with 2 rhizoid furrows and without an assimilatory strip with air chambers. This subgenus currently contains two species, M. quadrata and M. romanica.

Published as part of Long, David G., Forrest, Laura L., Villarreal, Juan Carlos & Crandall-Stotler, Barbara J., 2016, Taxonomic changes in Marchantiaceae, Corsiniaceae and Cleveaceae (Marchantiidae, Marchantiophyta), pp. 77-80 in Phytotaxa 252 (1) on page 78, DOI: 10.11646/phytotaxa.252.1.9, http://zenodo.org/record/13676556