BFNA Title: Myriniaceae
Author: P. Majestyk 
Date: January 8, 2008
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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Piers Majestyk


Plants small to medium in size, in loose or dense mats, yellowish green.  Stems creeping, pinnately to subpinnately or irregularly branched.  Branches short and blunt, terete to sometimes slightly flattened, horizontally spreading, often flagelliform-attenuate.  Paraphyllia none.  Stem and branch leaves similar or different, loosely appressed when dry, somewhat spreading when moist, concave, ovate to ovate-lanceolate, bluntly acute to obtuse or acuminate, margins entire to serrulate, decurrent or not; costa absent, short and double or single, faint, 1/4--1/2 the leaf length, at times unevenly divided distally; cells firm-walled and smooth or mammillose at back by projecting upper ends, proximal laminal cells oblate to quadrate near the margins, medial and distal laminal cells rhombic, oblong-rhomboidal or elongate- to linear-hexagonal.  Sexual condition autoicous (phyllodioicous) or dioicous.  Perigonial leaves ovate, shortly acute, ecostate, proximal cells bulging-rectangular, medial and distal cells rhombic to linear.  Perichaetial leaves sheathing, exterior leaves short, ovate, interior leaves oblong-lanceolate, ecostate; proximal cells rectangular to long-hexagonal, medial and distal cells rhombic to linear.  Seta yellow to reddish brown, elongate, twisted.  Capsule erect to suberect, light to dark brown, oblong to oblong-cylindric, smooth, annulus absent; peristome double; exostome teeth 16, bordered, yellow, cross-striolate in proximal 3/4, distal portion lightly papillose or nearly smooth, slightly trabeculate; endostome segments 16, yellow, equaling length of the exostome, lightly papillose; cilia rudimentary or none; basal membrane low; operculum convex-conic or obliquely conic-rostrate, blunt to short-pointed.  Calyptra cucullate, smooth, naked.  Spores spherical, papillose, yellow to light brown.


Genera 7, species ca. 30 (2 genera, 2 species in the flora); Arctic, temperate or subtropical regions.


SELECTED REFERENCES: Crum, H. A. and L. E. Anderson. 1981. Mosses of Eastern North America. 2 vols. New York.  Nyholm, E. 1960. Illustrated Moss Flora of Fennoscandia. 2 vols. Malmo, Sweden. 


1. Leaves entire; median and distal laminal cells short-rhomboidal; costa single . . . 1. Myrinia


1. Leaves serrulate; median and distal laminal cells oblong-rhomboidal; costa absent or faint, short and double . . . 2. Schwetschkeopsis


1. MYRINIA Schimper, Syn. Musc. Eur., 483. 1860 * [For Swedish bryologist Claes Gustav Myrin]


Plants small. Stems freely branched.  Stem and branch leaves similar; costa single, 1/4--1/2 leaf length.  Sexual condition autoicous.  Seta pale yellow.  Capsules oblong-cylindric; operculum convex-conic.


Species 2 (1 in the flora); largely restricted to Arctic regions.


SELECTED REFERENCES: Crum, H. A. & L. E. Anderson. 1981. Mosses of Eastern North America. 2 vols. New York.  Nyholm, E. 1960. Illustrated Moss Flora of Fennoscandia. 2 vols. Malmo, Sweden. 


1. Myrinia pulvinata (Wahlenberg) Schimper., Syn. Musc. Eur. 483, 1860; Leskea pulvinata Wahlenberg, Fl. Lapp. 369. 1812


Leaves oblong-ovate, rounded obtuse to bluntly acute, 0.65--0.9 x 0.3--0.5 mm; proximal cells 9--24 x 11--21 \um, medial and distal cells 22--34 x 11--13 \um.  Seta 6--10 mm. Capsule 1.15--1.75 mm; exostome teeth triangular-lanceolate, 325--365 x 80--95 \um.  Spores 14.5--19.5 \um, yellow.


Capsules mature May--Aug.  Areas submerged at flood level, bases of trees or shrubs, especially willows, edges of ponds or stream valleys; 0--1700 m; B.C., N.W.T., N.B., Ont.; Alaska; Europe; Asia (NW Siberia).


Myrinia pulvinata may be mistaken for species of Leskea because of similar habitat and leaf shape. Leskea species generally have a much stronger costa as well as papillose leaf cells.  When sporophytes are present, Myrinia’s cross-striolate external exostome surface is distinctive.  Myrinia pulvinata and Leskea polycarpa are often found growing intertwined.


2. SCHWETSCHKEOPSIS Brotherus, Nat. Pflanzenf. 1(3): 877. 1907 * [Segregate of Schwetschkea, for Karl Gustav Schwetschke, bookseller of Halle, 1804--1881]


Plants small to medium sized.  Stems somewhat flattened to terete, usually conspicuously wider than branches.  Branches prostrate or ascending, often flagelliform, generally all pointing in the same direction.  Stem and branch leaves similar in shape but often noticeably differentiated in size; costa absent or short and double.  Sexual condition phyllodioicous.  Seta orangish red, fading to yellow with age.  Capsules oblong-cylindric; operculum obliquely conic-rostrate.


Species ca. 6 (1 in the flora); temperate and subtropical regions.


SELECTED REFERENCES: Buck, W. R. and B. Goffinet. 2000. Morphology and classification of mosses. In: Bryophyte Biology. 2000. A. J. Shaw & B. Goffinet, eds. Pp. 71-123. Cambridge.  Crum, H. A. and L. E. Anderson. 1981. Mosses of Eastern North America. 2 vols. New York.  Reese, W. D. 1984. Mosses of the Gulf South. Baton Rouge, LA.


1. Schwetschkeopsis fabronia (Schwägrichen) Brotherus, Nat. Pflanzenf. 1(3): 878. 1907; Helicodontium fabronia Schwägrichen, Sp. Musc. Suppl. 3(2): 294. 1830; Leskea denticulata Sullivant; Schwetschkea denticulata (Sullivant) Cardot; Schwetschkeopsis denticulata (Sullivant) Brotherus


Plants slender, in small to rather large mats, olive-dark green.  Stems creeping, pinnately branched.  Branches simple or rarely with small secondary branches.  Leaves ovate-lanceolate, acute to mm; proximal cells 8--17 x0.25--0.35acuminate, loosely appressed, 0.5--0.7 x 10--13, median and distal cells 30--50 x 7--10 \um, often mammillose at back due to projecting distal ends.  Seta 4--8 mm.  Capsule 1--1.4 mm; exostome teeth triangular-lanceolate, 240--350 x 40--50 \um.  Spores 11--16 \um, yellow.


Only 4 collections (2 each from Florida and Tennessee) were observed with mature sporophytes (2 in October, 2 in February).  Bases of hardwoods, rocks (both acidic and basic); 125--1230 m; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Ky., La., Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va.; West Indies (Cuba); Asia (China, Japan, Korea, Russian Federation).


Schwetschkeopsis fabronia is a very slender, delicate moss with typically a “combed” appearance due to the branches generally being directed downward in an orderly fashion.  Clasmatodon parvulus is somewhat similar and often occurs with S. fabronia.  In the field Clasmatodon can generally be distinguished from Schwetschkeopsis by its dull color and rather “unkempt” appearance.  Also the stem and branches of Clasmatodon are similar in size while in Schwetschkeopsis the stem is generally noticeably larger than the branches.  Microscopically the two are easily separated by the well-developed single costa of Clasmatodon versus the faint, short and double or frequently absent costa of Schwetschkeopsis.  Many colonies of Schwetschkeopsis have stems composed almost entirely or in part, of long, flagellate branches.  Both H. A. Crum and L. E. Anderson (1981) and W. D. Reese (1984) report Schwetschkeopsis as being ecostate but many leaves exhibit a very faint, short, double costa. Recent (W. R. Buck and B. Goffinet 2000) molecular evidence suggests that Schwetschkeopsis might be more closely allied to the members of Anomodontaceae than the Myriniaceae.