Pylaisia Bruch, Schimp. & W. Gümbel, Bryologia Europaea

Pylaisia Bruch, Schimp. & W. Gümbel, Bryologia Europaea View in CoL 5: 87 (fasc. 46–47. Monogr. 1). 1851, nom. cons.

Plants small to medium-sized, light-, yellowish- or dark-green, silk-glossy, in flat, rather dense tufts or creeping by individual shoots upon thin twigs. Stems regularly pinnately to fasciculately branched, terete or complanate, in transverse section round to ovoid, with central strand, without hyalodermis; axillary hais 3-5 celled; first proximal branch leaf in lateral position to branch bud, entire to incised, and occasionally split to base, margin coarsely toothed to irregularly incised. Stem leaves straight to homomallous, erect to falcate-secund or even circinate, ovate-lanceolate to broadly ovate, gradually or abruptly tapered to long or short acumen, slightly to strongly and abruptly tapered to leaf insertion, more or less concave; margins plane, recurved at base or incurved at places, subentire to serrulate below the apex; costa short and double; median laminal cells rhomboidal to linear; alar cells subquadrate to rectangular, forming more or less well-defined group which is elongate along the margins or triangular, or sometimes wider than long. Branch leaves smaller and relatively narrower, sometimes lanceolate. Autoicous. Inner perichaetial leaves erect, oblong-lanceolate, more or less plicate. Setae long. Capsules erect, symmetric, cylindrical to broadly ovoid and sometimes subglobose. Operculum conic to rostrate. Annulus separated by fragments, composed of thick-walled quadrate cells. Peristome perfect, with exostome and endostome free, to strongly modified, with endostome partly or totally adherent to exostome teeth; all peristomes xerocastique, reflexing after wetting. Exostome teeth smooth below, papillose above. Endostome segments entire or perforated along keel or split by keel into halves, occasionally split at basal membrane level and entire above. Spores 10–35 µm, mature in winter. Calyptra cucullate.