Amphidiaceae
Autoicous or dioicous (not in Victoria). Asexual propagules absent. Dense cushions on rocks. Stems erect, repeatedly dichotomously branched, with dense rhizoids at base or sparsely covered throughout with rhizoids; central strand absent. Leaves narrowly lanceolate or oblong-lanceolate to linear, erect- to wide-spreading when moist, twisted and contorted or crisped when dry, tristichous; apex acute or acuminate; costa single, subpercurrent, percurrent or short-excurrent (not in Victoria); margin entire to dentate in apical half, plane or narrowly recurved toward base, without a border; laminal cells rounded-quadrate, rounded-hexagonal or oblate, pluripapillose on both surfaces over lumen and cell walls , appearing longitudinally striate, becoming rectangular, hyaline and smooth (not in Victoria) or less papillose toward base, unistratose; alar cells not differentiated. Capsule immersed or emergent, erect, symmetric, oblong or pyriform, 8-ribbed and urceolate when dry, without an annulus. Calyptra cucullate, smooth or papillose, glabrous. Operculum conic-apiculate (not in Victoria) to rostrate. Peristome absent.
One genus and six species shared between northern temperate regions, Central America, the Caribbean Islands, South America (south to Bolivia), South Africa, Macaronesia, south-east Asia, high altitude mountains of East Africa, New Guinea, New Zealand and the larger islands of the south-west Pacific, and eastern Australia (Sim-Sim et al. 2017); one species in Victoria.
Inferring the correct family placement of Amphidium remained unsettled due to the absence of a peristome in Amphidium and a set of morphological features that show some similarities to several families. This resulted in Amphidium being placed in the Dicranaceae, Orthotrichaceae and the Rhabdoweisiaceae. The costal anatomy of Amphidium contains median guide cells, absent from the Orthotrichaceae, but papillose laminal cells and sometimes calyptra, which are both more typical of the Orthotrichaceae (Lewinsky 1976). Phylogenies based on DNA sequences have provided an additional independent source of data for resolving the placement of Amphidium. These phylogenies suggest derivation from single peristome species, dismissing an affinity with Orthotrichaceae that belong to the lineage of mosses with double peristomes (Stech 1999; Cox et al. 2010). However, Amphidium was well-separated from both Dicranaceae and Rhabdoweisiaceae in phylogenies (La Farge et al. 2000; Cox et al. 2010; Stech et al. 2012; Fedosov et al. 2021), which when combined with its distinctive combination of morphological features provides ample reason for its recognition as a separate family (Stech & Frey 2008).
Frahm et al. (2000) conducted a worldwide morphological revision of Amphidium and reduced the number of species from thirteen (Crosby et al. 1992) to three. Sim-Sim et al. (2017) found this reduction to be excessive and instead recognised six species. These six species corresponded to six separate lineages in a combined chloroplast and nuclear DNA phylogeny that could be distinguished from each other morphologically. Their phylogeny also demonstrated that A. tortuosum (Hornsch.) Cufod. in the broad sense treated by Frahm et al. (2000) was potentially non-monophyletic. `
Cox, C.J.; Goffinet, B.; Wickett, N.J.; Boles, S.B.; Shaw, A.J. (2010). Moss diversity: A molecular phylogenetic analysis of genera. Phytotaxa 9: 175–195.
Crosby, M.R.; Magill, R.E.; Bauer, C.R. (1992). Index of Mosses, 1963–89. Missouri Botanical Garden, St Louis.
Fedosov, V.E.; Fedorova, A.V.; Larraín, J.; Santos, M.B.; Stech, M.; Kučera, J.; Brinda, J.C.; Tubanova, D.Y.; Von Konrat, M.; Ignatova, E.A.; Ignatov, M.S. (2021). Unity in diversity: phylogenetics and taxonomy of Rhabdoweisiaceae (Dicranales, Bryophyta). Botanical Journal of the Linnean Society 195: 545–567.
Frahm, J.-P.; Klöcker, T.; Schmidt, R.; Schöter, C. (2000). Revision der gattung Amphidium (Musci, Dicranaceae). Tropical Bryology 18: 171–184.
La Farge, C.; Mishler, B.D.; Wheeler, J.A.; Wall, D.P.; Johannes, K. (2000). Phylogenetic relationships within the haplolepidous mosses. The Bryologist 103(2): 257–276.
Sim-Sim, M.; Afonina, O.M.; Almeida, T.; Désamoré, A.; Laenen, B.; Garcia, C.A.; González-Mancebo, J.M.; Stech, M. (2017). Integrative taxonomy reveals too extensive lumping and a new species in the moss genus Amphidium (Bryophyta). Systematics and Biodiversity 15: 451–463.
Stech, M. (1999). A molecular systematic contribution to the position of Amphidium Schimp. (Rhabdoweisiaceae, Bryopsida). Nova Hedwigia 68: 291–300.
Stech, M.; Frey, W. (2008). A morpho-molecular classification of the mosses (Bryophyta). Nova Hedwigia 86: 1–21.
Stech, M.; McDaniel, S.F.; Hernández-Maqueda, R.; Ros, R.M.; Werner, O.; Muñoz, J.; Quandt, D (2012). Phylogeny of haplolepideous mosses – challenges and perspectives. Journal of Bryology 34: 173–186.