BFNA Title: Plagiotheciaceae
Author: R. R. Ireland 
Date: August 28, 2003
Edit Level: R Brum+
Version: 1a

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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Plagiotheciaceae

 

XXX. PLAGIOTHECIACEAE (Brotherus) M. Fleischer

 

Robert R. Ireland

 

Plants somewhat small to robust, in loose to dense mats or tufts.  Stems prostrate, mostly complanate but sometimes subjulaceous or erect and julaceous, simple or sparsely and irregularly branched; exterior layer of cortical cells large and thin-walled; rhizoids smooth or minutely papillose, sometimes present just distal to leaf insertion; pseudoparaphyllia lacking.  Leaves of stems and branches similar, flaccid, imbricate to distant, sometimes second with apices pointing toward substratum, smooth, erect or spreading, scarcely altered when dry, decurrent, often concave, ovate, ovate-lanceolate, oblong-lanceolate or oblong-ovate, acute, acuminate, rarely piliferous, symmetric or often asymmetric; margins plane or recurved, entire or serrulate to serrate at extreme apex; costa short and double, one branch sometimes reaching to midleaf and costa appearing single, or rarely ecostate; rhizoids at base on abaxial surfaces or adjacent cells, sometimes at leaf tips, smooth; cells smooth, walls usually with few pits at base, rarely pitted to leaf middle; median and distal cells linear, linear-flexuose or sometimes linear-rhomboidal, mostly thin-walled and heavily chlorophyllose, smooth; alar cells differentiated, equally distributed on either side of the costa, extending to decurrencies, the walls ± evenly thickened. Specialized asexual reproduction often present as propagula, cylindrical to fusiform, uniseriate, smooth walled, borne on branched stalks clustered in leaf axils, each propagulum consisting of several cells, or sometimes borne in clusters without stalks on abaxial surface of leaf and sometimes at leaf tips. Sexual condition autoicous, less commonly dioicous.  Seta solitary, smooth, elongate, straight, twisted, curved or rarely circinate.  Capsule cernuous or erect, rarely pendulous, straight or arcuate; exothecial cells thin- or thick-walled; annulus present, often persistent; operculum conic to rostrate, shorter than urn; annulus differentiated in 1--3 rows, deciduous, sometimes tardily so; peristome double, exostome teeth on exterior surface cross-striolate proximally, papillose distally, or rarely papillose throughout, projecting on interior surface; endostome with a medium to high basal membrane, the segments broad or narrow, keeled, not or very narrowly perforate, shorter than or almost as long as teeth, the cilia well developed to lacking. Calyptra cucullate, smooth, naked, fugacious. Spores spherical to ovoid, smooth or papillose.

 

Genus 1, species ca. 80--90 (6 in the flora); primarily in temperate latitudes and at higher elevations in the tropics; worldwide, including Antarctica.

 

Although I (W. R. Buck and R. R. Ireland 1985) presently take the view of including only one genus, namely Plagiothecium, in the Plagiotheciaceae, several other bryologists have included other genera, especially those in the Hypnaceae, in the family, e.g., E. Nyholm (1965), A. J. E. Smith (1978), S.-H. Lin (1984),  L. Hedenäs (1989, 1995) and N. Pedersen and L. Hedenäs (2002). Plagiothecium undulatum (Hedwig) Bruch, Schimper & W. Gümbel has recently been described as a new genus, Buckiella by R. R. Ireland (2001) and placed in the Hypnaceae.

 

SELECTED REFERENCES   Buck, W. R. and R. R. Ireland.  1985.  A reclassification of the Plagiotheciaceae.  Nova Hedwigia 41: 89--125.  Hedenäs, L.  1995.  Higher taxonomic level relationships among diplolepidous pleurocarpous mosses- a cladistic view.  J. of Bryology 18: 723--781.  Pederson, N. and L. Hedenäs.  2002.  Phylogeny of the Plagiotheciaceae based on molecular and morphological evidence.  Bryologist 105(3): 310--324.

 

1. PLAGIOTHECIUM Schimper in Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 179.  1851 * [Greek, plagios, oblique; theca, case, referring to the capsule]

 

Stereodon sect. Plagiothecium (Schimper) Mitten

 

Plants dark green to yellow-green, glossy or sometimes dull. Stems 20--60 × 0.5--4 mm. Leaves 0.7--3 × 0.4--2 mm; median leaf cells 36--180 × 3--21 µm, apical cells often shorter, basal cells shorter and broader; decurrent alar regions triangular or often auriculate and oval in outline, consisting of 1--8 longitudinal rows of spherical, oval, quadrate, or rectangular cells. Specialized asexual reproduction present as smooth-walled propagula borne on stems and branches, 2--7-celled, uniseriate bodies or in clusters without stalks on abaxial surface of leaf and sometimes at leaf tips. Sexual condition usually autoicous; perigonia and perichaetia numerous at bases of stems; perigonial bracts short, lanceolate to ovate, acuminate to filiform-acuminate; perichaetial leaves moderately enlarged, sheathing with somewhat spreading apices. Seta yellow, or orange to red-brown, Capsule yellow, or orange to red-brown, oblong to ovoid, often contracted under mouth when dry, smooth to striate, often wrinkled at neck; cilia 1--3, nodulose, as long as or nearly as long as the segments, rarely rudimentary or lacking.

 

Species ca. 80--90 (6 in the flora); North America, Central America, South America, Europe, Asia, Africa, Australia, Pacific Islands (New Guinea), Antarctic.

 

This is a genus of terrestrial habitats found in coniferous and deciduous woods, on rotten logs, stumps, bases of trees, humus and soil, frequently overlying acidic cliffs and boulders, sometimes in swamps and marshes, in temperate, boreal and Arctic regions, and at high elevations in the tropics.

 

SELECTED REFERENCES   Ireland, R. R.  1969.  A taxonomic revision of the genus Plagiothecium for North America, north of Mexico.  Natl. Mus. Canada, Natl. Mus. Nat. Sci., Publ. Bot. 1: 1--118.  Ireland, R. R.  1986.  Synopsis of the genus Plagiothecium for North America.  Lindbergia 12: 49--56.  Ireland, R. R.  1987.  Scanning electron microscope study of the spores of the North American species of Plagiothecium.  Mem. New York Bot. Gard. 45: 95--110.                  

 

1.  Leaf decurrencies composed of many inflated, quadrate to spherical cells; leaf margins broadly recurved nearly to apices. 

2. Plants julaceous; leaves with acuminate recurved apices, median cells 6--12 μm wide . . . . 5.  Plagiothecium berggrenianum

2. Plants complanate, rarely julaceous; leaves with acute apices, seldom recurved, median cells 12--20 μm wide. . . . 4. Plagiothecium denticulatum

1.  Leaf decurrencies composed or mostly rectangular cells; leaf margins plane or narrowly recurved.

3.  Leaf apices abruptly contracted to long-filiform, flexuose acumens, sometimes 1/3 length of leaves . . . . 1. Plagiothecium piliferum

3.  Leaf apices not abruptly contracted to filiform acumens.

4.  Leaves asymmetric and flat . . . . 6.  Plagiothecium laetum

4.  Leaves symmetric and concave.

5.  Plants large, stems to 40 × 1--4 mm; leaves often imbricate with tips recurved when dry, median cells 7--17 μm wide; occurring in mesic to somewhat xeric habitats . . . . 3.  Plagiothecium cavifolium

5.  Plants small, stems to 20 × 0.5--1 mm; leaves erect-spreading with straight tips, median cells 4--10 μm wide; occurring in hydric habitats . . . . 2.  Plagiothecium latebricola

 

1. Plagiothecium piliferum (Hartman) Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 186.  1851 (fasc. 48 Mon. 8.3)

 

Leskea pilifera Hartman, Handb. Skand. Fl. 419.  1820; Dolichotheca pilifera (Hartman) Podpĕra; Isopterygium piliferum (Hartman) Loeske; Plagiotheciella pilifera (Hartman) Brotherus

 

Plants light- to yellowish-green, glossy, usually in dense mats.  Stems to 60 × 1--1.5 mm, prostrate, complanate-foliate to subjulaceous.  Leaves imbricate, smooth, usually concave, symmetric, 0.8--2.0 × 0.4--0.8 mm, oblong-ovate, abruptly contracted to a long-filiform, flexuose acumen, sometimes 1/3 length of leaf, margins usually narrowly recurved nearly to apex, entire or minutely serrulate at apex; costa short and double, ending a short distance above leaf base, sometimes lacking; leaf cells smooth, walls of basal cells pitted; median cells 36--96 × 3--5 μm; decurrent alar region triangular in outline, consisting of 2--4 vertical rows of rectangular cells, 16--75 × 7--20 μm, terminating at the base in a single cell.  Specialized asexual reproduction  unknown.  Sexual condition autoicous, often fruiting.  Seta yellow to red, straight, 0.8--1.5 cm.  Capsule light brown to yellowish or reddish brown when mature, erect or sometimes slightly inclined, straight, 1--4 × 0.5--1 mm, smooth or slightly wrinkled when dry, strongly wrinkled at neck, usually contracted below mouth; operculum conic, 0.4--0.7 mm; cilia usually lacking, or 1--2 rudimentary, fragile cilia present.  Spores 9--13 μm.    

 

Capsules mature spring--summer.  Common in coniferous or alder-maple woods, trees (usually alder, rarely maple), rotten logs, noncalcareous cliffs and boulders; sometimes on wood in swampy areas; 30--1500 m; Greenland; B.C., N.W.T., Que.; Alaska, Calif., Idaho, Oreg., Mont., Wash.; Europe; Asia.

 

Plagiothecium piliferum is very distinctive.  Although its main center of distribution is in the Pacific Northwest, it has disjunctive occurrences in northern Quebec (James Bay region) and southwestern Greenland.  The concave, symmetric leaves with abruptly contracted, long-filiform, flexuose acumens, sometimes 1/3 the leaf length, and the erect, straight capsules make identification easy. A scanning electron microscope study of the spores of Plagiothecium (R. R. Ireland 1987) revealed that the sculpturing can be used to distinguish P. piliferum from the other North American species.  Spores of P. piliferum have branched-baculate ornamentation, the elements are covered with conic-papillae, while the other species have gemmate ornamentation, the elements covered with high-conic to low, rounded papillae.

 

2.  Plagiothecium latebricola Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 184 (fasc.48 Mon. 6.1).  1851

 

Isopterygium latebricolum (Bruch, Schimper & W. Gümbel) Delogne; Leskea latebricola (Bruch, Schimper & W. Gümbel) Wilson; Plagiotheciella latebricola (Bruch, Schimper & W. Gümbel) M. Fleischer

 

Plants light- to yellowish-green, glossy, in dense mats.  Stems to 20 × 0.5--1 mm, prostrate to erect, irregularly branched with numerous short branches.  Leaves imbricate, erect-spreading, smooth, usually concave, often symmetric, 0.7--1.5 × 0.2--0.5 mm, ovate-lanceolate, acuminate, margins plane or narrowly recurved nearly to apex, entire or sometimes with a few serrulations at apex; costa short and double, ending a short distance distal to leaf base, often lacking; leaf cells smooth, walls of basal cells pitted; median cells 52--150 × 4--10 μm; decurrent alar region triangular in outline, consisting of 1--5 vertical rows of rectangular cells, 26--72 × 12--19 μm, terminating in a single cell at the base.  Specialized asexual reproduction by propagula usually present, 57--108 × 7--14 μm, consisting of 3--6 cells borne on leaf stalks in leaf axils or in clusters without stalks on abaxial surface of leaf or sometimes at leaf tips.  Sexual condition dioicous, rarely fruiting.  Seta light brown to orange-brown, straight, 0.6--1 cm.  Capsule light brown to orange-brown when mature, erect, rarely inclined, straight or rarely somewhat arcuate, 0.5--1.2 × 0.2--0.6 mm, smooth, not contracted below mouth, slightly wrinkled at neck when dry; operculum conic-apiculate to short-rostrate, 0.4--0.6 mm; cilia lacking, or with 1--2 rudimentary cilia.  Spores 9--13 μm. 

 

Capsules mature summer.  Swamps, fens, marshes, and inundated woods on rotten logs, stumps, bases of trees, and humus; 50--75 m; N.B., Nfld., N.S., Ont., Que.; Conn., Mass., Mich., N.J., N.Y., Ohio, Pa., Wis.; Europe.

 

This is a rare species of northeastern North America where it always occurs in wet habitats.  It is the smallest species in the genus and is recognized by short stems of up to 2 cm, erect-spreading, mostly symmetric, somewhat concave leaves that are 0.7--1.5 mm, median cells 4--10 μm wide, tapering decurrencies composed of rectangular cells, and erect, straight capsules that are not contracted under the mouth. Reports of this species from western North America are evidently erroneous and probably are mostly P. laetum, which it closely resembles.

 

3.  Plagiothecium cavifolium (Bridel) Iwatsuki, J. Hattori Bot. Lab. 33: 360.  1970

 

Hypnum cavifolium Bridel, Bryol. Univ. 2: 556.  1827; Leskea flaccida Bridel; Plagiothecium aciculari-pungens J.K.A. Müller & Kindberg; P. attenuatirameum Kindberg in Macoun & Kindberg; P. fallax Cardot & Thériot; P. roeseanum Bruch, Schimper & W. Gümbel; P. sullivantiae (Sullivant) A. Jaeger

 

Plants pale green to yellowish green, glossy, rarely dull, in thin to dense mats.  Stems to 40 × 1--4 mm, erect, sometimes prostrate, usually julaceous, rarely somewhat complanate-foliate, often flagelliform and attenuate at apices.  Leaves imbricate, rarely distant, usually erect, sometimes spreading, smooth, strongly concave, rarely nearly flat, usually symmetric, 1--3 × 0.4--1.4 mm, ovate or oblong-ovate, abruptly acute or slenderly acuminate, apex often recurved, margins plane or often narrowly recurved nearly to apex, entire or rarely serrulate near apex; costa short and double, one branch often reaching leaf middle, sometimes one branch poorly developed and costa appearing single, or costa rarely lacking; leaf cells smooth, walls of basal cells pitted; median cells 60--161 × 7--17 μm; decurrent alar region triangular in outline, consisting of 1--5 vertical rows of rectangular cells, 28--70 × 12--22 μm, terminating at the base in a single cell.  Specialized asexual reproduction by propagula sometimes present, 36--110 × 9--17 μm, consisting of 2--7 cells borne on branched stalks in leaf axils.  Sexual condition dioicous, rarely fruiting. Seta light brown to red, straight or somewhat curved, 1--2.6 cm.  Capsule light brown to dark red when mature, erect to inclined, straight or often arcuate, 1--2.5 × 0.3--0.8 mm, when dry contracted below mouth, smooth or often striate or wrinkled, strongly wrinkled at neck; operculum rostrate, 0.8--1 mm; cilia 1--3.  Spores 9--14 μm.  

 

 

Capsules mature spring--summer.  Shaded soil or humus overlying boulders and cliffs, sometimes on rotten logs, stumps, and bases of trees; 40--1980 m; Greenland; B.C., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que., Yukon; Ala., Alaska, Ark., Calif., Colo., Conn., D.C., Ga., Idaho, Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., S.C., S.Dak., Tenn., Vt., Va., Wash., W.Va., Wis.; Europe; Asia.

 

The julaceous plants with concave, recurved leaf apices are distinctive characters, and help distinguish P. cavifolium from the other North American species.  The species is very similar to P. sylvaticum (Bridel) Bruch, Schimper & W. Gümbel of Europe; P. cavifolium, however, is usually julaceous with concave leaves that have narrow median cells, 7--17 μm wide, while P. sylvaticum is complanate-foliate with flat leaves whose median cells are broader, 12--22 μm wide. The California record is from a report by K. McGrew (1976).

 

4.  Plagiothecium denticulatum (Hedwig) Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 190. 1851 (fasc. 48 Mon. 12.8)

 

Hypnum denticulatum Hedwig, Sp. Musc. 237. 1801; H. donnianum Smith; H. obtusifolium (Turner) Bridel; Plagiothecium denticulatum var. bullulae Grout; P. ruthei Limpricht; P. sandbergii Renauld & Cardot; P. sylvaticum var. squarrosum Kindberg

 

Plants dark green to yellowish green, dull or glossy, in thin to dense mats.  Stems to 50 × 1--4 mm, prostrate, rarely erect, complanate-foliate or sometimes julaceous.  Leaves usually imbricate, rarely secund with some apices pointing toward substratum, flat to concave, usually asymmetric, 1.5--4 × 0.5--2 mm, oblong-ovate or ovate-lanceolate, acute to acuminate, rarely narrowly obtuse, margins broadly recurved nearly to apex or sometimes plane, serrulate at extreme apex, rarely entire; costa short and double, one branch sometimes reaching the leaf middle, or costa rarely lacking; leaf cells smooth, walls of basal cells with a few pits, rarely pitted to leaf middle; median cells 70--180 × 12--21 μm; decurrent alar region often auriculate and oval in outline, consisting of 3--8 vertical rows of spherical, oval, quadrate, and rectangular cells, 19--80 × 19--29 μm, usually terminating at the base in several spherical or oval cells, sometimes alar region triangular in outline, composed of quadrate and rectangular cells, terminating at the base in a single cell.  Specialized asexual reproduction by propagula often present, 72--178 × 9--24 μm, consisting of 3--7 cells borne on branched stalks in leaf axils.  Sexual condition autoicous, sometimes dioicous, often fruiting.  Seta light brown to red, often curved, 1.5--3.5 cm long.  Capsule light brown to orange-brown when mature, cernuous and arcuate, rarely nearly straight and erect or inclined, 1.5--3.5 × 0.5--1 mm, when dry, strongly contracted below mouth, striate or sometimes wrinkled, rarely smooth, strongly wrinkled at neck; operculum short-rostrate, 0.7--1 mm; cilia 2--3.  Spores 9--13 μm. 

 

Capsules mature summer.  Woods on rotten logs, stumps, bases of trees, or on humus or soil frequently overlying boulders and cliffs; 50--2740 m; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., Nun., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Maine, Md., Mass., Mich., Minn., Mo., Mont., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; Asia; Africa.

 

This is one of the most common and one of the most variable species of Plagiothecium in North America.  The plants have complanate stems to 50 mm, mainly flattened, asymmetric, acute leaves, 1.5--4 mm, with broadly recurved margins, decurrencies that are often auriculate, composed of inflated, quadrate or spherical cells, median cells 12--21 μm wide, capsules 1.5--3.5 mm, inclined to horizontal, slightly curved, and urns distinctly striate when dry.  Sometimes, especially in western North America, the stems are julaceous, to about 3 cm, the leaves are strongly concave, nearly symmetric, narrowly obtuse, 1.5--2 mm, and the capsules are almost straight and erect. Plagiothecium denticulatum has been reported for Australia and New Zealand but an examination of the specimens from those regions revealed that they are another species, P. novae-seelandiae Brotherus (R. R. Ireland 1992).

 

5.  Plagiothecium berggrenianum Frisvoll, Lindbergia 7: 96. 1981

 

Plants light- to yellowish-green, glossy, in dense tufts.  Stems to 80 × 1--1.5 mm, erect, julaceous.  Leaves closely imbricate, smooth, concave, symmetric, 1.5--2.5 × 0.8--1.2 mm, ovate or oblong-ovate, acuminate, apex usually recurved, margins broadly recurved throughout, entire or denticulate near apices; costa short and double, one branch sometimes reaching 1/3 length of leaf; leaf cells smooth, walls of basal cells pitted; median cells 85--141 × 6--12 μm; decurrent alar region triangular or rarely somewhat oval in outline, consisting of 2--4 vertical rows of rectangular or inflated, oval cells, 40--60 × 9--24 μm, terminating at the base in a single cell.  Specialized asexual reproduction unknown. Sexual condition and sporophyte unknown.

 

Swales, wet tundra and rocky slopes and cliffs; 0--1220 m; Greenland; N.W.T.; Alaska; Europe (Norway).

 

This is an Arctic species that has been confused with P. cavifolium, or julaceous forms of P.  laetum and P. denticulatum.  The acuminate leaves with recurved apices will separate P. berggrenianum from P. denticulatum, while the inflated, oval cells in the decurrencies will distinguish it from P. cavifolium and P. laetum.

 

6.  Plagiothecium laetum Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 185.  1851 (fasc. 48 Mon. 7.2)

 

Plagiothecium curvifolium Limpricht; P. decursivifolium Kindberg; P. denticulatum var. laetum (Bruch, Schimper & W. Gümbel) Lindberg; P. denticulatum var. microcarpum Renauld & Cardot; P. denticulatum var. tenellum Bruch, Schimper & W. Gümbel; P. laetum var. neomexicanum Cardot

 

Plants light- to yellowish-green, glossy, in dense mats.  Stems to 20 × 1--3(4) mm, prostrate, complanate-foliate, rarely somewhat julaceous.  Leaves imbricate, rarely distant, erect or spreading, often slightly undulate, sometimes secund with apices pointing toward substratum, usually asymmetric, 0.7--2.6 × 0.3--1.2 mm, oblong-ovate or ovate-lanceolate, slenderly acuminate, margins plane or often narrowly recurved nearly to apex, usually entire or with a few serrulations at apices; costa short and double, ending a short distance above leaf base, rarely with one branch reaching leaf middle, or costa sometimes lacking; leaf cells smooth, walls of basal cells pitted; median cells 96--168 × 4--10 μm; decurrent alar region triangular in outline, consisting of 1--5 vertical rows of rectangular cells, 40--100 × 9--29 μm, terminating at the base in a single cell.  Specialized asexual reproduction by propagula usually present, 40--86 × 8--14 μm, consisting of 3--6 cells borne on branched stalks in leaf axils.  Sexual condition autoicous, often fruiting.  Seta orange-brown to red, straight or curved, 1--1.6 cm.  Capsule light- to orange-brown when mature, erect to cernuous, straight to arcuate, 0.5--2.0 × 0.4--0.7 mm, when dry smooth or rarely wrinkled when arcuate; operculum conic to short-rostrate, 0.3--0.8 mm; cilia 1--3, sometimes lacking.  Spores 9--14 μm.   

 

Capsules mature summer.  Usually in coniferous woods on rotten logs, stumps, bases of trees, humus or soil, frequently overlying boulders and cliffs; 75--3050 m; Greenland; Alta., B.C., Man., N.B., Nfld., N.W.T., Nun., N.S., Ont., P.E.I., Que., Yukon; Alaska, Calif., Colo., Conn., Idaho, Iowa, Maine, Mass., Mich., Minn., Mont., N.H., N.J., N.Mex., N.Y., N.C., Ohio; Oreg., Pa., Tenn., Vt., Va., Wash., W.Va., Wis.; Europe; Asia.

 

Plagiothecium laetum has a past history (R. R. Ireland 1969) of being confused with P. denticulatum in North America.  The small leaves, 0.7--2.6 mm, with narrower median cells, 4--10 μm wide, the decurrencies that are triangular in outline and composed of rectangular cells, and the usually smooth capsules will distinguish P. laetum from P. denticulatum, which has larger leaves, 1.5--4 mm, broader median cells, 12--21 μm wide, decurrencies usually oval in outline and composed of some oval cells, and capsules striate when dry. I prefer to include Plagiothecium curvifolium Schliephacke in the synonymy of P. laetum.  Plants referred to P. curvifolium have smooth secund leaves pointing toward the substratum, decurrencies of 3--5 rows of cells, composed of rectangular cells mixed with some inflated, quadrate or spherical cells, and capsules usually cernuous and often arcuate.  However, I have found that these characters do not always correlate and the plants seem best considered environmental forms of the variable P. laetum.

 

 

OTHER REFERENCES

Hedenäs, L.  1989.  Some neglected character distribution patterns among pleurocarpous mosses.  Bryologist 92: 157--163.

Lin, S.-H.  1984.  A taxonomic revision of Phyllogoniaceae (Bryopsida).  Part II.  J. Taiwan Museum 37(2): 1--54.

Ireland, R. R..  1992.  Studies of the genus Plagiothecium in Australasia.  Bryologist 95: 221--224.

Ireland, R. R.  2001.  Buckiella, a new genus in the Hypnaceae (Musci).  Novon 11: 55--62.

McGrew, K.  1976.  Bryophytes of the Russian Peak Area, Siskiyou County, California.  M.A. Thesis, Humboldt State Univ., Arcata 62 pp.

Nyholm, E.  1965.  Illustrated Moss Flora of Fennoscandia II.  Musci.  Fasc. 5.   Plagiotheciaceae. Pp. 620--647.  Lund.

Smith, A. J. E.  1978.  The Moss Flora of Britain and Ireland.  Plagiotheciaceae. Pp. 621--638.  Cambridge.