Trematodon Michx. 1803
Long-necked mosses
Taxonomy The genus Trematodon (Bruchiaceae) has been poorly circumscribed and is in need of revision. There are over 80 published names with only about 25 species well characterized (Zander, 2007).
Habitat Trematodon mosses are terrestrial mosses found in many areas. These mosses are most commonly found growing on moist soil along roads or streams in open, disturbed areas (Crum, 1983). The specimen of Trematodon ambiguus that I collected was found growing on soil from a recently uprooted tree.
Distribution Trematodon is distributed worldwide with the largest diversity in northern temperate forests. Europe, eastern Asia, Canada, and the United States (Crum, 1983).
Gametophyte The gametophyte of Trematodon is minute to small. It is yellow-green to green in color with the leaves twisted (similar to Dicranum) on dry material. The leaves are entire, lanceolate to broadly subulate, and have an acute to narrowly obtuse apex (Zander, 2007). The leaf cells are smooth, small, and subquadrate or short-rectangular (Crum, 1983). The specimens of Trematodon ambiguus I collected had stems that were not close together forming a loose mat on the soil.
Sporophyte The sporophyte of the Trematodon is quite distinctive being bright yellow in color. The sporophyte is exserted and held high above the gametophyte. Crum (1983) describes the capsules of the Trematodon as erect or somewhat curved with a conspicuous neck (common name derived from this character). The capsule is operculate with or without an obvious peristome of 16 simple, forked or rostrate teeth (Zander, 2007)
Literature Cited
Crum, H. 2004. Mosses of the Great Lakes Forest. Ann Arbor, MI: University of Michigan Herbarium.
Zander, R. H. 2007. Trematodon. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. Vol. 27, pp. 433-439.
Written by Jeremy Keene
May 2010