Encalypta Hedw.

Elements in the following description are taken from Horton (1983).

Plants acrocarpous, medium-sized, green to olive-green, often with yellow-brown or red-brown overtones. Stems variable in length, to 50 mm (rarely more), more or less branched, in cross-section with or without a distinct central strand. Leaves mostly oblong to lingulate, rather abruptly narrowed above to a broadly acute or obtuse apex, muticous, mucronate, apiculate, or with a long hair-point, much contorted and usually inrolled when dry, erect-spreading to reflexed when moist, broadly V-shaped in cross-section; margins crenulate or entire, plane or recurved below; upper laminal cells unistratose, short-oblong or rounded-quadrate, bulging, densely pluripapillose; cells of lower lamina elongate-oblong, smooth, extending upwards to 1/3 or more of the leaf length, with thin longitudinal walls and thickened and mostly pigmented transverse walls (especially near base of costa); cells of the lower margin often narrower and more elongate to form a moderately defined border; alar cells not differentiated. Costa stout, ending well below leaf apex to excurrent, mostly prominent abaxially, in cross-section with 2–3 central layers of large and often thick-walled cells, a distinct abaxial stereid band (mostly of 2–3 cell layers) and a single adaxial layer of green, papillose cells. Gemmae absent in N.Z. taxa (rarely present and axillary in non-N.Z. species).

Gonioautoicous (in N.Z. species) or rarely dioicous. Perichaetia terminal, the leaves not or weakly differentiated, often overtopped by innovations. Perigonia mostly immediately below the perichaetia. Setae rather short, straight or flexuose, variable twisted; capsules, erect, exserted, narrowly cylindric, with a weakly defined neck, smooth, weakly striate, or furrowed, ± constricted at mouth when dry, with a small and poorly defined neck; exothecial cells variably oblong, thin-walled; stomata superficial to indistinctly immersed, restricted to capsule base or scattered on urn; annulus mostly absent, sometimes differentiated; operculum conic-rostrate, short to very elongate. Peristome extremely variable, often nil. Spores highly variable, spherical or reniform, often with distinct proximal and distal surfaces and often ± trilete. Calyptra narrowly long-mitrate, completely enclosing the capsule, usually weakly lobed at base, in N.Z. species c. 4.5–6 mm.

Horton (1983) considered Encalypta to comprise 19 species, many of which are predominantly or exclusively distributed in the colder parts of the northern hemisphere. Fewer species occur at higher elevations in the tropics and in temperate to cold parts of the southern hemisphere. Two species are known from N.Z.

The extraordinarily variable nature of the peristome in Encalypta, a group otherwise so "naturally cohesive" (Horton, 1982, p. 368), has long attracted attention from bryologists. Horton discussed this variability from an historical perspective. Ironically, both the N.Z. species are gymnostomous. She also pointed out (Horton, 1982, 1983) that the peristome variation is paralleled by a high level of spore morphology variation, which she illustrated in detail using SEM micrographs.

Horton (1983) also discussed the presence of populations in North America that appeared to show intermediates between E. vulgaris and E. rhaptocarpa, but resisted reducing these two taxa to infraspecific rank. The two taxa seem clearly differentiated in N.Z., although our material of E. rhaptocarpa appears to be consistently gymnostomous, unlike populations in some other parts of its range.

The commonly produced and disproportionately large calyptrae and gymnostomous capsules, together with the unbordered and entire leaves of both N.Z. Encalypta species, should preclude confusion with members of the Pottiaceae. Of the most likely confused species, Hennediella macrophylla and H. arenae have relatively large and ± campanulate calyptrae but their leaves are bordered above, and denticulate at the apex. Both species of Hennediella lack the pigmented and thickened transverse walls in the basal cells that characterise all Encalypta spp.

Sterile material of either Encalypta species could possibly be confused in N.Z. with Syntrichia antarctica or S. anderssonii. However, sterile material of Encalypta is very rarely collected. The calyptrae and distinctly thickened transverse walls in the interior basal cells of all Encalypta species again distinguish the genus. In both our Encalypta spp. the margins are plane or nearly so and the basal marginal cells lack chlorophyll; in Syntrichia spp. the margins are generally narrowly recurved and the basal marginal cells are pigmented.