Plagiothecium denticulatum var. denticulatum (Hedw.) Schimp., Bryologia Europea 5: 190, 501, Tab. VIII. 1851. ≡ Hypnum denticulatum Hedw., Species Muscorum Frondsorum 237. 1801 ≡ Stereodon denticulatus (Hedw.) Brid., Bryologia Universa 2: 824. 1827 ≡ Pancovia denticulata (Hedw.) J. Kickx f., Flore Cryptogamique des Flandres 1: 93. 1867. Lectotype (designated by Ireland 1969): Germany, Starke, G 000420240! = Plagiothecium denticulatum var. bullulae Grout, North American Musci Perfecti 450 1942. Lectotype (designated here): U. S. A., Idaho, Elmore Co., Boise National Forest, on soil and base of saplings by small water course above cemetery, 22 Sep. 1942, F. A. MacFadden, C-M- 9386! Isolectotypes: MO- 406576, NY 505676, NY 507145. = Plagiothecium sylvaticum var. rupestre Warnst. ex Grav., Bulletin de la Société Royale de Botanique de Belgique 19: 31. 1880. Lectotype (designated here): Germany, Bavar. Australis, ad rupes silic. umbros. montium editiorum Silvae Gabretae, parietes verticals investiens, ca. 800–1000 m, Aug 1879, sub “ P. silvaticum var. rupestre Progel ”, Progel, PC 0132568! Isolectotypes: Germany Baiern, Waldmünchen am Böhmerwald, auf Gneissfelsen im Juni, Progel, PC 0132569! syn. nov. Description. Plants medium-sized, light to dark green, with metallic luster; stems 2–5 cm long; leaves complanate, more julaceous in lower part of stem, concave, ovate, asymmetrical, with two rounded sides, rounded asymmetric, 1.5–3.0 × 0.5–2.0 mm (Fig. 1 A); the apex acute to acuminate; margins denticulate near the apex; laminal cells 80–130 × 10–14 μm at midleaf (Fig. 1 D), cell areolation quite loose; decurrencies well developed, consisting of 4–5 rows of spherical, inflated cells; capsule inclined. Distribution. Asia (Azerbeijan, Bangladesh, China, Democratic People’s Republic of Korea, Iraq, India, Islamic Republic of Iran, Japan, Kazakhstan, Kyrgystan, Mongolia, Nepal, Pakistan, Republic of Korea, Russian Federation); Europe (Albania, Andorra, Armenia, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Kosovo, Latvia, Lichtenstein, Lithuania, Luxembourg, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania); North America (Canada, U. S. A.).

Published as part of Wolski, Grzegorz J., 2025, The genus Plagiothecium (Plagiotheciaceae) in Europe — current state of knowledge, checklist and key to taxa, pp. 67-102 in PhytoKeys 253 on pages 67-102, DOI: 10.3897/phytokeys.253.142268