Taxonomic novelties in Scapania Author Vana, Jiri Department of Botany, Charles University, Benatska 2, 128 01 Praha 2, Czech Republic Author Hentschel, Joern Department of Systematic Botany with Herbarium Haussknecht and Botanical Garden, Friedrich Schiller University, Fuerstengraben 1, 07743 Jena, Germany Author Mueller, Jochen Department of Systematic Botany with Herbarium Haussknecht and Botanical Garden, Friedrich Schiller University, Fuerstengraben 1, 07743 Jena, Germany Author Heinrichs, Jochen Department of Systematic Botany, Albrecht von Haller Institute of Plant Sciences, Georg August University, Untere Karspuele 2, 37073 Goettingen, Germany jheinrichs@lmu.de text PhytoKeys 2012 2012-03-12 10 13 17 http://dx.doi.org/10.3897/phytokeys.10.2654 journal article http://dx.doi.org/10.3897/phytokeys.10.2654 1314-2003-10-13 1F1D3F774E46FFB9364FFFA9FF947A52 576112 Scapania sect. Americanae Vana , Hentschel, Joch. Muell . & Heinrichs sect. nov. Diagnosis. The new section of Scapania subg. Scapania is characterized by its type, the dioicous Scapania americana Muell . Frib. Distinctive features of Scapania americana and Scapania sect. Americanae are thick-walled, pigmented stem epidermis cells with thinner-walled cells on the ventral side of the stem, closely and sharply ciliate-dentate leaf-margins, with largest teeth up to five cells long and terminal cells considerably longer than wide, leaf-lobes that are usually decurrent beyond the level of the keel, a verruculose or striate-verruculose cuticle, and two-celled gemmae at the margins of unmodified leaves. The dorsal leaf-lobes often develop an undulate or folded base and may even show minute lobules or auricles. Type. Scapania americana Muell . Frib., Bull. Herb. Boissier, ser . 2, 3: 44. 1902. Note. Scapania americana is placed sister to Scapania sect. Compactae ( Muell . Frib.) H. Buch with weak bootstrap support ( Heinrichs et al. 2012 ). It differs from members of Scapania sect. Compactae by its dioicous condition; hence we place it in a new section rather than in sect. Compactae . In our current circumscription, Scapania sect. Americanae is monospecific, however, extension of the taxon sampling in forthcoming molecular studies may disclose further representatives.