BFNA Title: Trachycystis
Author: J. D. Bainard 
Date: September 8, 2008
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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XX.  TRACHYCYSTIS Lindberg, Not. Sällsk. Fauna Fl. Fenn. Förh.9: 80. 1868 * [Greek trachy, rough, and cystis, bladder, alluding to the mammillose laminal cells]


                                                                                                                    J. D. Bainard


Plants medium sized, in dense tufts, yellowish green. Stems erect; rhizoids reddish brown, proximally numerous. Branch leaves well spaced, contorted when dry, erect-spreading, flat or weakly keeled when wet, ovate-elliptic, decurrent; margins plane, 1-stratose, 2-serrate; apex acute to acuminate; costa single, percurrent; distal and medial laminal cells hexagonal to isodiametric, mammillose on both surfaces, thick-walled, collenchymatous; marginal cells linear. Sexual condition dioicous. [Seta red, flexuose. Capsule horizontal to pendent, obovate; annulus deciduous; operculum convex-conic; peristome short and blunt, yellow to yellowish green; endostome yellow-brown, with a high basal membrane, segments perforate with gaps along keels and well-developed cilia in groups of 2--3, nodulose.]


Species 3 (1 in the flora): circumtemperate.


Trachycystis is a monotypic genus in North America, distinguished from other genera in the Mniaceae by mammillose distal and medial laminal cells.


SELECTED REFERENCES Kabiersch, W. 1936. Studien über die ostasiatischen Arten einiger Laubmoosfamilien (Mniaceae--Bartramiaceae). Hedwigia 76: 1--95. Frahm, J. 2001. Neue Laubmoosfunde aus Sächsischem und Baltischem Bernstein. Nova Hedwigia 72: 271--281.


1. Trachycystis flagellaris (Sullivant & Lesquereux) Lindberg,

Contributio ad Floram Cryptogamam Asiae Boreali-Orientalis, 241. 1872


Mnium flagellare Sullivant & Lesquereux, Proc. Amer. Acad. Arts Sci. 4: 277. 1859


Stems (0.7--)1--2.5 cm, with few branches. Branch leaves reddish, smaller and distant proximally, crisped when dry, erect-spreading when wet, ovate-elliptic, (0.8--)1--2.6 x 0.5--1.7 mm, decurrent; margins with sharp, paired teeth in the distal 2/3; apex acute to acuminate; costa percurrent, reddish, toothed dorsally; median laminal cells (9--)12--18  x (9--)12--15(--21) \um; alar cells differentiated, inflated, thin-walled, rectangular, 2--3\x larger than medial cells; marginal cells linear, in 2 rows. Specialized asexual reproduction as flagelliform branches, 2--4 mm, from the axils of comal leaves, with small, appressed, spaced leaves. [Seta 2--3 cm, red, flexuose. Capsule occasional, subpendulous, yellowish brown, obovate, 2--3 mm; peristome yellow-green.  Spores 20 \um, papillose, brownish yellow.]


Capsules mature summer. Cliffs, humus, boulders, shaded habitats and forests, epiphyte on alder and birch; low elevations; Alaska; Europe; Asia.


Trachycystis flagellaris is distinguished from other species in the genus by the distinctive leaf border. The asexual mode of reproduction via flagelliform branches is also observed in Dicranum flagellare. Sporophyte description is based on Asian material.


SELECTED REFERENCE Williams, R. S. 1912. Mnium flagellare Sull. & Lesq. in North America. Bryologist 15: 10.