Classification
 Nomenclature
Scientific Name:
Triquetrella Müll.Hal., Österr. Bot. Z. 47: 421 (1897)
Type Taxon:
Triquetrella tristicha (Müll.Hal.) Müll.Hal.
Etymology:
The generic name refers to the leaves being arranged in three ranks: triquetrus (three-angled) + ella (diminutive).
 Description

The following generic description is modified from Zander (1993).

Plants yellow- or glaucous-green above, brown below, forming dense to lax interwoven mats on soil or rock. Stems irregularly branched, to 70 mm, in cross-section usually rounded-triangular, central strand absent or small, sclerodermis present. Leaves usually in 3 distinct ranks, erect-spreading to spreading when moist, usually appressed to incurved and flexuose when dry, triangular to ovate-triangular (in N.Z. species), acute to acuminate, margins variably recurved in basal ½ to ⅘ of leaf, entire to weakly serrulate (crenulate from bulging papillose cells in N.Z. species); upper laminal cells obscure, round-rhombic to quadrate, firm- to thick-walled, papillose; marginal cells not differentiated; lower laminal cells differentiated weakly in a very small group medially, or occasionally not differentiated. Costa strong, percurrent or occasionally failing before the apex; adaxial superficial cells elongate and smooth to weakly papillose; abaxial superficial cells papillose throughout; in cross-section with two stereid bands. Axillary hairs to 9 cells with basal 1–2 cells thick-walled. Laminal KOH colour reaction yellow (in N.Z. species) to orange.

Dioicous. Perichaetia terminal, or terminal and lateral in the same species and occasionally on the same plant, with inner leaves strongly sheathing the seta. Perigonia terminal and lateral in clusters (not seen in N.Z. material). Setae elongate. Capsules cylindric to ellipsoid. Operculum conic or rostrate. Peristome of 16 teeth, short, straight, variously cleft, lacking a basal cylinder. Spores 10–17 µm, papillose.

 Taxonomy

A genus of about 10 species, found in Australasia, South Africa, southern South America, western North America, and Europe; usually in Mediterranean climates. Molecular studies (Hedderson & Zander 2007​​​​​​​) indicate a relationship with the genus Leptodontium, confirming the detailed morphological analyses of Zander (1993)​​​​​​​.

Two species occur in N.Z., both of which are Australasian in distribution.

 Key
1Shoots terete when dry and with leaves closely appressed; stems red; leaf margins decurrent on stem; laminal cells thick-walled, with 1–2 papillae per cellT. papillata
1'Shoots catenulate when dry and with leaves flexuose-twisted; stems green to brown; leaf margins not decurrent on stem; laminal cells firm-walled with c. 4 papillae per cellT. tasmanica
 Biostatus
Indigenous (Non-endemic)
Number of species in New Zealand within Triquetrella Müll.Hal.
CategoryNumber
Indigenous (Non-endemic)2
Total2
 Bibliography
Beever, J.E. 2024: Pottiaceae subfamily Barbuloideae. In: Heenan, P.B. (ed.) Flora of New Zealand — Mosses. Fascicle 50. Manaaki Whenua Press, Lincoln.
Goffinet, B.; Buck, W.R.; Shaw, A.J. 2009: Morphology, anatomy, and classification of the Bryophyta. In: Goffinet, B.; Shaw, A.J. (ed.) Bryophyte Biology. Edition 2. Cambridge University Press, Cambridge. 55–138.
Hedderson, T.A.; Zander, R.H. 2007: Triquetrella mxinwana, a new moss species from South Africa, with a phylogenetic and biogeographic hypothesis for the genus. Journal of Bryology 29: 151–160.
Müller, C. 1897: Triquetrella genus muscorum novum coditum et descriptum. Österreichische Botanische Zeitschrift 47: 420–424.
Zander, R.H. 1993: Genera of the Pottiaceae: mosses of harsh environments. Bulletin of the Buffalo Society of Natural Sciences 32: i–vi, 1–378.