BFNA Title: Pylaisia
Author: T. Arikawa 
Date: January 23, 2010
Edit Level: R 
Version: 1

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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Hypnaceae - Pylaisia

 

XX. PYLAISIA Schimper in P. Bruch, W. P. Schimper & W. T. Gümbel, Bryol. Eur. 5(46--47): 87. 1851, conserved bane * [For A. J. M. Bachelot de la Pylaie, 1786--1856, French Bryologist]

Tomotsugu Arikawa

 

Pylaisiella Kindberg ex Grout

 

Plants small to large, in low, yellowish to whitish green, shiny mats.  Stems creeping, terete to flattened, regularly or irregularly pinnately branched, central strand present, small, without hyalodermis; branches complanate to subjulaceous, usually creeping, sometimes ascending;  pseudoparaphyllia foliose, triangular to semicircular, dentate.  Stem leaves straight to falcate, broadly ovate-lanceolate to narrowly oblong-lanceolate; costa short and double or indistinct; medial laminal cells linear or linear-rhomboidal, smooth; alar regions somewhat or broadly differentiated, extending upwards along leaf margins; alar cells subquadrate to rectangular, homogeneous.  Branch leaves smaller or almost the same size, narrowly ovate- to oblong-lanceolate. Sexual condition autoicous.  Inner perichaetial leaves erect, oblong-lanceolate, irregularly but distinctly serrulate at the shoulders or slightly serrulate only distally, more or less plicate, sometimes involute.  Seta smooth, sinistrorsely twisted basally, dextrorsely twisted distally when dry; capsules erect, oblong-cylindric to ovoid; operculum conic to rostrate, obliquely short- to rather long-acute or obtuse; stomata phaneropore, few, on base of neck; exothecial cells rounded-rectangular or variously shaped.  Peristome perfect to reduced, hygroscopic, incurved when dry, erect when wet; exostome teeth 16, lance-subulate to blunt, distinctly lamellate, smooth basally, sometimes roughly papillose distally on the outer surface, closely trabeculate on the inner surface; endostome free or adherent to exostome teeth, with a basal membrane, segments keeled, perforate or not, sometimes 2-fid, or fragmentary, cilia rudimentary.  Spores spherical [or somewhat tetrapozoidal by endosporic protonemata], papillose.  Calyptra cucullate, smooth, split to near the apex.

 

Species 16 (4 in the flora): North America, Central America, South America (Andes Mountains), Europe, Asia.

 

SELECTED REFERENCES   Ando, H. and M. Higuchi. 1987.  Pylaisiella steerei (Hypnaceae), a new moss species from Alaska.  Mem. New York Bot. Gard. 45: 211--215.  Arikawa, T. 2004. A taxonomic study of the genus Pylaisia (Hypnaceae, Musci). J. Hattori Bot. Lab. 95: 71--154.

 

1. Endostome segments free, deeply keeled, neither 2-fid nor perforate; spores usually small, less than 16 \um; stem leaves usually long, more than 1.3 mm.

2. Branches subjulaceous; stem and branch leaves slightly differentiated; stem leaves substraight; subquadrate alar cells of stem leaves 5--12(--15) along the margins; endostome extending 0.30--0.38 mm beyond the mouth..........1. Pylaisia polyantha

2. Branches more or less complanate, only partly subjulaceous and scarcely curved; stem and branch leaves more markedly differentiated and usually falcate; subquadrate alar cells of stem leaves 10--15(--18), along the margins; endostome extending 0.38--0.50 mm beyond the mouth..........2. Pylaisia steerei

1 Endostome segments wholly or partially adherent to exostome teeth, 2-fid or fragmentary; spores usually large, more than 16 \um; stem leaves usually short, less than 1.2 mm.

3. Bifid endostome segments free distally; stems regularly and densely pinnately branched;  subquadrate alar cells of branch leaves numerous, 20--25 along the margins............3. Pylaisia selwynii

3. Bifid endostome segments wholly adherent; stems irregularly pinnately branched; subquadrate alar cells of branch leaves few, 6--12 along the margins.............4. Pylaisia intricata

 

1. Pylaisia polyantha (Hedwig) P. Bruch, W. P. Schimper & W. T. Gümbel, Bryol. Eur. 5(46--47): 88. 1851 (‘Pylaisaea’)

 

Leskea polyantha Hedwig, Sp. Musc. Frond., 229. 1801; Isothecium polyanthum (Hedwig) Spruce;  Pterogonium polyanthos (Hedwig) G. H. E. Muhlenberg; Pylaisia cyrtophylla Kindberg; P. denticulata Schimper ex Sullivant; P. filari-acuminata Müller Hal. & Kindberg; P. jamesii Sullivant & Lesquereux; P. ontariensis Müller Hal. & Kindberg; P. polyantha var. jamesii (Sullivant & Lesquereux) Rau & Hervey; P. polyantha var. subdenticulata (Schimper) Rau & Hervey;  P. pseudoplatygyrium Kindberg; P. subdenticulata Schimper; P. suttonii Jennings; Pylaisiella polyantha (Hedwig) Grout; P. subdenticulata (Schimper) Grout; Stereodon polyanthos (Hedwig) Mitten; S. subdenticulatus (Schimper) Mitten

 

Plants rather small, in low yellowish or whitish green, shiny mats.  Stems prostrate, to 2 cm, yellowish brown, terete to flattened, somewhat regularly pinnately branched; branches subjulaceous, to 10 mm, usually creeping, only rarely ascending and curved;  pseudoparaphyllia foliose, triangular, long-acuminate, dentate.  Stem and branch leaves slightly differentiated.  Stem leaves nearly straight, ovate-lanceolate, gradually narrowed to a long acumen, 1.3--2.0 x 0.4--0.5 mm, concave, slightly plicate; margins plane, sometimes slightly involute distally, subentire to serrulate distally; costa short and double; median laminal cells linear, 50--80 x 4--5 \um, smooth; alar cells subquadrate to rectangular, homogeneous, 8--10 along the margins, in 5--8 rows.  Branch leaves rather shorter, narrowly ovate-lanceolate, 1.1--1.4 x 0.3--0.5 mm. Inner perichaetial leaves erect, to 1.4 mm long, oblong-lanceolate, suddenly narrowed to a short acumen, irregularly but distinctly serrulate at the shoulders, more or less plicate.  Seta yellowish or reddish brown, 10--18 mm, sinistrorsely twisted in basal 3/4--4/5 and dextrorsely twisted in distal 1/4--1/5 when dry; capsules erect, reddish brown, oblong-cylindric, somewhat widened at base, 1.6--2.2 mm excluding operculum, 0.4--0.6 mm wide; operculum conic, obliquely short-pointed; exothecial cells rounded-rectangular, uniformly thin-walled.  Peristome perfect, rather long; exostome teeth lance-subulate, ca. 0.2 mm, ca. 70 \um wide at base, smooth basally, slightly papillose distally on the outer surface; endostome free, with a well-developed basal membrane, segments linear-subulate, longer than exostome teeth, ca. 0.3 mm, papillose distally, keeled but not perforate, never split, cilia simple, rudimentary.  Spores 11--14 \um, slightly papillose.

 

Tree trunks; low to high elevations; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Colo., Conn., D.C., Ill., Iowa, Ky., Maine, Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Pa., R.I., S.Dak., Tex., Vt., Va., Wis.; Mexico; Europe; Asia (Russia).

 

Pylaisia polyantha is the type species of the genus. It is the most widely distributed of the species and is remarkably variable.  More than 20 varietal taxa have been described, but they are yet to be revised (T. Arikawa 2004).

 

2. Pylaisia steerei (Ando & Higuchi) Ignatov, Arctoa 10: 174. 2001

 

Pylaisiella steerei Ando & Higuchi, Mem. New York Bot. Gard. 45: 211, f. 1--34. 1987

 

Plants small, in low yellowish or whitish green, shiny mats.  Stems prostrate, to 2 cm, yellowish brown, terete, regularly pinnately branched; branches more or less complanate, partly subjulaceous, to 5 mm, usually creeping, only rarely ascending and curved;  pseudoparaphyllia foliose, triangular, long acuminate, dentate.  Stem and branch leaves rather well differentiated.  Stem leaves substraight to falcate, broadly ovate-lanceolate, gradually narrowed to a long acumen, 1.4--1.6 x 0.4--0.65 mm, concave, not plicate; margins plane, sometimes slightly involute distally, subentire to serrulate distally; costa short and double; median laminal cells linear, 40--60 x 4--5 \um, smooth; alar cells subquadrate to rectangular, homogeneous, comparatively numerous, 10--15 along the margins, in 5--10 rows.  Branch leaves smaller, narrowly ovate- to oblong-lanceolate, 1.2--1.4 x 0.3--0.5 mm. Inner perichaetial leaves erect, oblong-lanceolate, suddenly narrowed to a short acumen, irregularly but distinctly serrulate at the shoulders, more or less plicate.  Seta yellowish or reddish brown, 7--11 mm, smooth, sinistrorsely twisted basally and dextrorsely twisted distally when dry; capsules erect, reddish-brown, oblong-cylindric, somewhat widened at base, 1.1--1.9 mm excluding operculum, 0.4--0.6 mm wide; operculum conic, obliquely short-pointed; exothecial cells rounded-rectangular, uniformly thin-walled.  Peristome perfect, rather long; exostome teeth lance-subulate, ca. 0.3 mm, 80 \um wide at base, smooth basally, roughly papillose distally; endostome free, with a well developed basal membrane, segments linear-subulate, longer than exostome teeth, papillose distally, keeled but not perforate, never split; cilia simple, rudimentary.  Spores 15--18 \um, finely papillose.

 

Rotten logs and base of tree trunks, forest, moderate to high elevations; Alaska; Asia (Far East Russia, nw China).

 

Pylaisia steerei is the closest relative of P. polyantha.  H. Ando and M. Higuchi (1987) provided full illustration, SEM micrographs of the peristome, and a detailed discussion of this species.  It is known from only three localities in Alaska in the flora region.

 

3. Pylaisia selwynii Kindberg, Ottawa Naturalist 2: 156. 1889 (“-i”)

 

Pylaisiella selwynii (Kindberg) H. A. Crum, Steere & L. E. Anderson; Pylaisia schimperi Cardot

 

Plants small, in yellowish to whitish green, shiny mats.  Stems creeping, to 2 cm, yellowish brown, terete to flattened, regularly and densely pinnately branched; branches subjulaceous, to 3 mm, ascending and strongly curved.  Pseudoparaphyllia foliose, triangular, strongly dentate.  Stem and branch leaves secund.  Stem leaves almost straight, broadly ovate-lanceolate, rather suddenly narrowed into a rather short acumen, cordate at base, 0.9--1.2 x 0.5--0.6 mm, not concave, not plicate; margins plane, sometimes slightly incurved distally, subentire to serrulate distally; costa short and double or indistinct; median laminal cells linear, rather short, 25--45 x 4.3--7.0 \um, smooth; alar cells subquadrate to rectangular, homogeneous, comparatively numerous, 20--25 along the margins, in 6--10 rows.  Branch leaves smaller, narrower, oblong-lanceolate, 0.7--0.9 x 0.25--0.30 mm.  Inner perichaetial leaves erect, oblong-lanceolate, to 1.6 mm, more longly acuminate than stem leaves; costa double and short or indistinct.  Seta yellowish or reddish brown, 10--15 mm, sinistrorsely twisted in basal half and dextrorsely twisted in distal half when dry; capsules erect to suberect, reddish brown, oblong-ovoid, 1.0--1.6 mm excluding operculum, 0.6 mm wide; operculum conic; exothecial cells variable in shape, thin-walled.  Peristome with exostome teeth lanceolate, 0.15--0.20 mm, 45--50 \um wide at base, surface smooth basally, finely papillose distally; endostome adherent to exostome teeth except distally; segments keeled and split; 2-fid segment and cilia united and adherent to inner surface of exostome teeth, with developed basal membrane except in upper 1/2 to 1/3; inner surface of endostome roughly and finely papillose.  Spores spherical, 16--25 \um, slightly papillose.

 

Tree trunks; moderate to high elevations; N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., Que., Yukon; Ala., Alaska, Ariz., Ark., Conn., Del., D.C., Fla., Ga., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Pa., Vt., Va., W.Va., Wis.; Mexico; Asia (sw China, Japan, Russia).

 

Pylaisia selwynii is the most frequent and common species in the genus in the flora area.  It is easily distinguished from the other species in the flora by the regularly and densely pinnately branched stems, broadly ovate-lanceolate stem leaves, comparatively numerous alar cells of the stem leaves, and adherent endostomes except for the distal portion.

 

4. Pylaisia intricata (Hedwig) Schimper in Bruch, Schimper & W. Gümbel, Bryol. Eur. 5: 88. 1854 (‘Pylaisaea’)

 

Pterigynandrum intricatum Hedwig, Sp. Musc. Frond., 85. 1801; Hypnum intricatum (Hedwig) Müller Hal.; Pterogonium intricatum (Hedwig) Schwägrichen; Pylaisia velutina Schimper; Pylaisiella intricata (Hedwig) Grout; Pylaisiella velutina (Schimper) Kindberg; Stereodon intricatus (Hedwig) Lindberg & Arnell

 

Plants rather small, in yellowish green, shiny mats.  Stems creeping, to 2 cm, yellowish brown, terete, irregularly pinnately branched; branches subjulaceous, to 5 mm, usually creeping, only ascending and curved in dense mats; pseudoparaphyllia foliose, triangular to semicircular, dentate.  Stem and branch leaves homomallous and erect-spreading when dry, wide-spreading when wet.  Stem leaves straight or somewhat falcate, ovate-lanceolate, rather suddenly narrowed into short acumen, cordate at base, 0.8--1.0 x 0.25--0.40 mm, not plicate; margins plane, subentire to serrulate distally; costa short and double; median laminal cells linear, 30--65 x 5--6 \um, smooth; alar cells subquadrate to rectangular, homogeneous, 6--12 along the margins, in 6--9 rows.  Branch leaves rather larger, oblong-lanceolate, 1.1--1.2 x 0.32--0.39 mm.  Inner perichaetial leaves to 2 mm, erect, oblong-lanceolate, more longly acuminate than stem leaves, scarcely serrulate at the apex, more or less plicate; costa double.  Seta yellowish or reddish brown, 20--24 mm, sinistrorsely twisted in basal half and dextrorsely twisted in distal half when dry; capsules erect to suberect, reddish brown, oblong-cylindrical, 1.8--2.0 mm excluding operculum, 0.65--0.7 mm wide; operculum rostrate, obliquely long-pointed; the distalmost vesiculose, deciduous; exothecial cells variable in shape, thin-walled.  Peristome with exostome teeth lanceolate, ca. 0.19 mm, ca. 50 \um wide at base, surface smooth basally, finely papillose distally; endostome adherent to exostome teeth; segments keeled and split; 2-fid segment and cilia united and adherent to inner surface of exostome teeth, with well developed basal membrane; inner surface of endostome roughly and finely papillose.  Spores spherical, 16--32 \um, slightly papillose.

 

Trunks of broad-leaved trees; moderate to high elevations; Alta., B.C., Man., N.B., N.W.T., N.S., Ont., Que.; Ala., Ariz., Colo., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Maine, Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

 

Pylaisia intricata is a rare species endemic to the flora region. It is characterized by rather small branch leaves, long-pointed operculum, finely papillose outer surface of the distal portion of exostome teeth, and adherent endostome.  It can be distinguished from P. polyantha by its adherent endostome and larger spores.